STL algorithm源码：stl_algo.h

<span style="font-size:18px;">// Algorithm implementation -*- C++ -*-// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009,// 2010, 2011// Free Software Foundation, Inc.//// This file is part of the GNU ISO C++ Library.  This library is free// software; you can redistribute it and/or modify it under the// terms of the GNU General Public License as published by the// Free Software Foundation; either version 3, or (at your option)// any later version.// This library is distributed in the hope that it will be useful,// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the// GNU General Public License for more details.// Under Section 7 of GPL version 3, you are granted additional// permissions described in the GCC Runtime Library Exception, version// 3.1, as published by the Free Software Foundation.// You should have received a copy of the GNU General Public License and// a copy of the GCC Runtime Library Exception along with this program;// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see// <http://www.gnu.org/licenses/>./* * * Copyright (c) 1994 * Hewlett-Packard Company * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation.  Hewlett-Packard Company makes no * representations about the suitability of this software for any * purpose.  It is provided "as is" without express or implied warranty. * * * Copyright (c) 1996 * Silicon Graphics Computer Systems, Inc. * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation.  Silicon Graphics makes no * representations about the suitability of this software for any * purpose.  It is provided "as is" without express or implied warranty. *//** @file bits/stl_algo.h *  This is an internal header file, included by other library headers. *  Do not attempt to use it directly. @headername{algorithm} */#ifndef _STL_ALGO_H#define _STL_ALGO_H 1#include <cstdlib>             // for rand#include <bits/algorithmfwd.h>#include <bits/stl_heap.h>#include <bits/stl_tempbuf.h>  // for _Temporary_buffer#ifdef __GXX_EXPERIMENTAL_CXX0X__#include <random>     // for std::uniform_int_distribution#include <functional> // for std::bind#endif// See concept_check.h for the __glibcxx_*_requires macros.namespace std _GLIBCXX_VISIBILITY(default){_GLIBCXX_BEGIN_NAMESPACE_VERSION  /// Swaps the median value of *__a, *__b and *__c to *__a  template<typename _Iterator>    void    __move_median_first(_Iterator __a, _Iterator __b, _Iterator __c)    {      // concept requirements      __glibcxx_function_requires(_LessThanComparableConcept<    typename iterator_traits<_Iterator>::value_type>)      if (*__a < *__b){  if (*__b < *__c)    std::iter_swap(__a, __b);  else if (*__a < *__c)    std::iter_swap(__a, __c);}      else if (*__a < *__c)return;      else if (*__b < *__c)std::iter_swap(__a, __c);      elsestd::iter_swap(__a, __b);    }  /// Swaps the median value of *__a, *__b and *__c under __comp to *__a  template<typename _Iterator, typename _Compare>    void    __move_median_first(_Iterator __a, _Iterator __b, _Iterator __c,_Compare __comp)    {      // concept requirements      __glibcxx_function_requires(_BinaryFunctionConcept<_Compare, bool,    typename iterator_traits<_Iterator>::value_type,    typename iterator_traits<_Iterator>::value_type>)      if (__comp(*__a, *__b)){  if (__comp(*__b, *__c))    std::iter_swap(__a, __b);  else if (__comp(*__a, *__c))    std::iter_swap(__a, __c);}      else if (__comp(*__a, *__c))return;      else if (__comp(*__b, *__c))std::iter_swap(__a, __c);      elsestd::iter_swap(__a, __b);    }  // for_each  /// This is an overload used by find() for the Input Iterator case.  template<typename _InputIterator, typename _Tp>    inline _InputIterator    __find(_InputIterator __first, _InputIterator __last,   const _Tp& __val, input_iterator_tag)    {      while (__first != __last && !(*__first == __val))++__first;      return __first;    }  /// This is an overload used by find_if() for the Input Iterator case.  template<typename _InputIterator, typename _Predicate>    inline _InputIterator    __find_if(_InputIterator __first, _InputIterator __last,      _Predicate __pred, input_iterator_tag)    {      while (__first != __last && !bool(__pred(*__first)))++__first;      return __first;    }  /// This is an overload used by find() for the RAI case.  template<typename _RandomAccessIterator, typename _Tp>    _RandomAccessIterator    __find(_RandomAccessIterator __first, _RandomAccessIterator __last,   const _Tp& __val, random_access_iterator_tag)    {      typename iterator_traits<_RandomAccessIterator>::difference_type__trip_count = (__last - __first) >> 2;      for (; __trip_count > 0; --__trip_count){  if (*__first == __val)    return __first;  ++__first;  if (*__first == __val)    return __first;  ++__first;  if (*__first == __val)    return __first;  ++__first;  if (*__first == __val)    return __first;  ++__first;}      switch (__last - __first){case 3:  if (*__first == __val)    return __first;  ++__first;case 2:  if (*__first == __val)    return __first;  ++__first;case 1:  if (*__first == __val)    return __first;  ++__first;case 0:default:  return __last;}    }  /// This is an overload used by find_if() for the RAI case.  template<typename _RandomAccessIterator, typename _Predicate>    _RandomAccessIterator    __find_if(_RandomAccessIterator __first, _RandomAccessIterator __last,      _Predicate __pred, random_access_iterator_tag)    {      typename iterator_traits<_RandomAccessIterator>::difference_type__trip_count = (__last - __first) >> 2;      for (; __trip_count > 0; --__trip_count){  if (__pred(*__first))    return __first;  ++__first;  if (__pred(*__first))    return __first;  ++__first;  if (__pred(*__first))    return __first;  ++__first;  if (__pred(*__first))    return __first;  ++__first;}      switch (__last - __first){case 3:  if (__pred(*__first))    return __first;  ++__first;case 2:  if (__pred(*__first))    return __first;  ++__first;case 1:  if (__pred(*__first))    return __first;  ++__first;case 0:default:  return __last;}    }  /// This is an overload used by find_if_not() for the Input Iterator case.  template<typename _InputIterator, typename _Predicate>    inline _InputIterator    __find_if_not(_InputIterator __first, _InputIterator __last,  _Predicate __pred, input_iterator_tag)    {      while (__first != __last && bool(__pred(*__first)))++__first;      return __first;    }  /// This is an overload used by find_if_not() for the RAI case.  template<typename _RandomAccessIterator, typename _Predicate>    _RandomAccessIterator    __find_if_not(_RandomAccessIterator __first, _RandomAccessIterator __last,  _Predicate __pred, random_access_iterator_tag)    {      typename iterator_traits<_RandomAccessIterator>::difference_type__trip_count = (__last - __first) >> 2;      for (; __trip_count > 0; --__trip_count){  if (!bool(__pred(*__first)))    return __first;  ++__first;  if (!bool(__pred(*__first)))    return __first;  ++__first;  if (!bool(__pred(*__first)))    return __first;  ++__first;  if (!bool(__pred(*__first)))    return __first;  ++__first;}      switch (__last - __first){case 3:  if (!bool(__pred(*__first)))    return __first;  ++__first;case 2:  if (!bool(__pred(*__first)))    return __first;  ++__first;case 1:  if (!bool(__pred(*__first)))    return __first;  ++__first;case 0:default:  return __last;}    }  /// Provided for stable_partition to use.  template<typename _InputIterator, typename _Predicate>    inline _InputIterator    __find_if_not(_InputIterator __first, _InputIterator __last,  _Predicate __pred)    {      return std::__find_if_not(__first, __last, __pred,std::__iterator_category(__first));    }  /// Like find_if_not(), but uses and updates a count of the  /// remaining range length instead of comparing against an end  /// iterator.  template<typename _InputIterator, typename _Predicate, typename _Distance>    _InputIterator    __find_if_not_n(_InputIterator __first, _Distance& __len, _Predicate __pred)    {      for (; __len; --__len, ++__first)if (!bool(__pred(*__first)))  break;      return __first;    }  // set_difference  // set_intersection  // set_symmetric_difference  // set_union  // for_each  // find  // find_if  // find_first_of  // adjacent_find  // count  // count_if  // search  /**   *  This is an uglified   *  search_n(_ForwardIterator, _ForwardIterator, _Integer, const _Tp&)   *  overloaded for forward iterators.  */  template<typename _ForwardIterator, typename _Integer, typename _Tp>    _ForwardIterator    __search_n(_ForwardIterator __first, _ForwardIterator __last,       _Integer __count, const _Tp& __val,       std::forward_iterator_tag)    {      __first = _GLIBCXX_STD_A::find(__first, __last, __val);      while (__first != __last){  typename iterator_traits<_ForwardIterator>::difference_type    __n = __count;  _ForwardIterator __i = __first;  ++__i;  while (__i != __last && __n != 1 && *__i == __val)    {      ++__i;      --__n;    }  if (__n == 1)    return __first;  if (__i == __last)    return __last;  __first = _GLIBCXX_STD_A::find(++__i, __last, __val);}      return __last;    }  /**   *  This is an uglified   *  search_n(_ForwardIterator, _ForwardIterator, _Integer, const _Tp&)   *  overloaded for random access iterators.  */  template<typename _RandomAccessIter, typename _Integer, typename _Tp>    _RandomAccessIter    __search_n(_RandomAccessIter __first, _RandomAccessIter __last,       _Integer __count, const _Tp& __val,        std::random_access_iterator_tag)    {            typedef typename std::iterator_traits<_RandomAccessIter>::difference_type_DistanceType;      _DistanceType __tailSize = __last - __first;      const _DistanceType __pattSize = __count;      if (__tailSize < __pattSize)        return __last;      const _DistanceType __skipOffset = __pattSize - 1;      _RandomAccessIter __lookAhead = __first + __skipOffset;      __tailSize -= __pattSize;      while (1) // the main loop...{  // __lookAhead here is always pointing to the last element of next   // possible match.  while (!(*__lookAhead == __val)) // the skip loop...    {      if (__tailSize < __pattSize)return __last;  // Failure      __lookAhead += __pattSize;      __tailSize -= __pattSize;    }  _DistanceType __remainder = __skipOffset;  for (_RandomAccessIter __backTrack = __lookAhead - 1;        *__backTrack == __val; --__backTrack)    {      if (--__remainder == 0)return (__lookAhead - __skipOffset); // Success    }  if (__remainder > __tailSize)    return __last; // Failure  __lookAhead += __remainder;  __tailSize -= __remainder;}    }  // search_n  /**   *  This is an uglified   *  search_n(_ForwardIterator, _ForwardIterator, _Integer, const _Tp&,   *       _BinaryPredicate)   *  overloaded for forward iterators.  */  template<typename _ForwardIterator, typename _Integer, typename _Tp,           typename _BinaryPredicate>    _ForwardIterator    __search_n(_ForwardIterator __first, _ForwardIterator __last,       _Integer __count, const _Tp& __val,       _BinaryPredicate __binary_pred, std::forward_iterator_tag)    {      while (__first != __last && !bool(__binary_pred(*__first, __val)))        ++__first;      while (__first != __last){  typename iterator_traits<_ForwardIterator>::difference_type    __n = __count;  _ForwardIterator __i = __first;  ++__i;  while (__i != __last && __n != 1 && bool(__binary_pred(*__i, __val)))    {      ++__i;      --__n;    }  if (__n == 1)    return __first;  if (__i == __last)    return __last;  __first = ++__i;  while (__first != __last && !bool(__binary_pred(*__first, __val)))    ++__first;}      return __last;    }  /**   *  This is an uglified   *  search_n(_ForwardIterator, _ForwardIterator, _Integer, const _Tp&,   *       _BinaryPredicate)   *  overloaded for random access iterators.  */  template<typename _RandomAccessIter, typename _Integer, typename _Tp,   typename _BinaryPredicate>    _RandomAccessIter    __search_n(_RandomAccessIter __first, _RandomAccessIter __last,       _Integer __count, const _Tp& __val,       _BinaryPredicate __binary_pred, std::random_access_iterator_tag)    {            typedef typename std::iterator_traits<_RandomAccessIter>::difference_type_DistanceType;      _DistanceType __tailSize = __last - __first;      const _DistanceType __pattSize = __count;      if (__tailSize < __pattSize)        return __last;      const _DistanceType __skipOffset = __pattSize - 1;      _RandomAccessIter __lookAhead = __first + __skipOffset;      __tailSize -= __pattSize;      while (1) // the main loop...{  // __lookAhead here is always pointing to the last element of next   // possible match.  while (!bool(__binary_pred(*__lookAhead, __val))) // the skip loop...    {      if (__tailSize < __pattSize)return __last;  // Failure      __lookAhead += __pattSize;      __tailSize -= __pattSize;    }  _DistanceType __remainder = __skipOffset;  for (_RandomAccessIter __backTrack = __lookAhead - 1;        __binary_pred(*__backTrack, __val); --__backTrack)    {      if (--__remainder == 0)return (__lookAhead - __skipOffset); // Success    }  if (__remainder > __tailSize)    return __last; // Failure  __lookAhead += __remainder;  __tailSize -= __remainder;}    }  // find_end for forward iterators.  template<typename _ForwardIterator1, typename _ForwardIterator2>    _ForwardIterator1    __find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,       _ForwardIterator2 __first2, _ForwardIterator2 __last2,       forward_iterator_tag, forward_iterator_tag)    {      if (__first2 == __last2)return __last1;      else{  _ForwardIterator1 __result = __last1;  while (1)    {      _ForwardIterator1 __new_result= _GLIBCXX_STD_A::search(__first1, __last1, __first2, __last2);      if (__new_result == __last1)return __result;      else{  __result = __new_result;  __first1 = __new_result;  ++__first1;}    }}    }  template<typename _ForwardIterator1, typename _ForwardIterator2,   typename _BinaryPredicate>    _ForwardIterator1    __find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,       _ForwardIterator2 __first2, _ForwardIterator2 __last2,       forward_iterator_tag, forward_iterator_tag,       _BinaryPredicate __comp)    {      if (__first2 == __last2)return __last1;      else{  _ForwardIterator1 __result = __last1;  while (1)    {      _ForwardIterator1 __new_result= _GLIBCXX_STD_A::search(__first1, __last1, __first2, __last2, __comp);      if (__new_result == __last1)return __result;      else{  __result = __new_result;  __first1 = __new_result;  ++__first1;}    }}    }  // find_end for bidirectional iterators (much faster).  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2>    _BidirectionalIterator1    __find_end(_BidirectionalIterator1 __first1,       _BidirectionalIterator1 __last1,       _BidirectionalIterator2 __first2,       _BidirectionalIterator2 __last2,       bidirectional_iterator_tag, bidirectional_iterator_tag)    {      // concept requirements      __glibcxx_function_requires(_BidirectionalIteratorConcept<  _BidirectionalIterator1>)      __glibcxx_function_requires(_BidirectionalIteratorConcept<  _BidirectionalIterator2>)      typedef reverse_iterator<_BidirectionalIterator1> _RevIterator1;      typedef reverse_iterator<_BidirectionalIterator2> _RevIterator2;      _RevIterator1 __rlast1(__first1);      _RevIterator2 __rlast2(__first2);      _RevIterator1 __rresult = _GLIBCXX_STD_A::search(_RevIterator1(__last1),       __rlast1,       _RevIterator2(__last2),       __rlast2);      if (__rresult == __rlast1)return __last1;      else{  _BidirectionalIterator1 __result = __rresult.base();  std::advance(__result, -std::distance(__first2, __last2));  return __result;}    }  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,   typename _BinaryPredicate>    _BidirectionalIterator1    __find_end(_BidirectionalIterator1 __first1,       _BidirectionalIterator1 __last1,       _BidirectionalIterator2 __first2,       _BidirectionalIterator2 __last2,       bidirectional_iterator_tag, bidirectional_iterator_tag,       _BinaryPredicate __comp)    {      // concept requirements      __glibcxx_function_requires(_BidirectionalIteratorConcept<  _BidirectionalIterator1>)      __glibcxx_function_requires(_BidirectionalIteratorConcept<  _BidirectionalIterator2>)      typedef reverse_iterator<_BidirectionalIterator1> _RevIterator1;      typedef reverse_iterator<_BidirectionalIterator2> _RevIterator2;      _RevIterator1 __rlast1(__first1);      _RevIterator2 __rlast2(__first2);      _RevIterator1 __rresult = std::search(_RevIterator1(__last1), __rlast1,    _RevIterator2(__last2), __rlast2,    __comp);      if (__rresult == __rlast1)return __last1;      else{  _BidirectionalIterator1 __result = __rresult.base();  std::advance(__result, -std::distance(__first2, __last2));  return __result;}    }  /**   *  @brief  Find last matching subsequence in a sequence.   *  @ingroup non_mutating_algorithms   *  @param  __first1  Start of range to search.   *  @param  __last1   End of range to search.   *  @param  __first2  Start of sequence to match.   *  @param  __last2   End of sequence to match.   *  @return   The last iterator @c i in the range   *  @p [__first1,__last1-(__last2-__first2)) such that @c *(i+N) ==   *  @p *(__first2+N) for each @c N in the range @p   *  [0,__last2-__first2), or @p __last1 if no such iterator exists.   *   *  Searches the range @p [__first1,__last1) for a sub-sequence that   *  compares equal value-by-value with the sequence given by @p   *  [__first2,__last2) and returns an iterator to the __first   *  element of the sub-sequence, or @p __last1 if the sub-sequence   *  is not found.  The sub-sequence will be the last such   *  subsequence contained in [__first,__last1).   *   *  Because the sub-sequence must lie completely within the range @p   *  [__first1,__last1) it must start at a position less than @p   *  __last1-(__last2-__first2) where @p __last2-__first2 is the   *  length of the sub-sequence.  This means that the returned   *  iterator @c i will be in the range @p   *  [__first1,__last1-(__last2-__first2))  */  template<typename _ForwardIterator1, typename _ForwardIterator2>    inline _ForwardIterator1    find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,     _ForwardIterator2 __first2, _ForwardIterator2 __last2)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)      __glibcxx_function_requires(_EqualOpConcept<    typename iterator_traits<_ForwardIterator1>::value_type,    typename iterator_traits<_ForwardIterator2>::value_type>)      __glibcxx_requires_valid_range(__first1, __last1);      __glibcxx_requires_valid_range(__first2, __last2);      return std::__find_end(__first1, __last1, __first2, __last2,     std::__iterator_category(__first1),     std::__iterator_category(__first2));    }  /**   *  @brief  Find last matching subsequence in a sequence using a predicate.   *  @ingroup non_mutating_algorithms   *  @param  __first1  Start of range to search.   *  @param  __last1   End of range to search.   *  @param  __first2  Start of sequence to match.   *  @param  __last2   End of sequence to match.   *  @param  __comp    The predicate to use.   *  @return The last iterator @c i in the range @p   *  [__first1,__last1-(__last2-__first2)) such that @c   *  predicate(*(i+N), @p (__first2+N)) is true for each @c N in the   *  range @p [0,__last2-__first2), or @p __last1 if no such iterator   *  exists.   *   *  Searches the range @p [__first1,__last1) for a sub-sequence that   *  compares equal value-by-value with the sequence given by @p   *  [__first2,__last2) using comp as a predicate and returns an   *  iterator to the first element of the sub-sequence, or @p __last1   *  if the sub-sequence is not found.  The sub-sequence will be the   *  last such subsequence contained in [__first,__last1).   *   *  Because the sub-sequence must lie completely within the range @p   *  [__first1,__last1) it must start at a position less than @p   *  __last1-(__last2-__first2) where @p __last2-__first2 is the   *  length of the sub-sequence.  This means that the returned   *  iterator @c i will be in the range @p   *  [__first1,__last1-(__last2-__first2))  */  template<typename _ForwardIterator1, typename _ForwardIterator2,   typename _BinaryPredicate>    inline _ForwardIterator1    find_end(_ForwardIterator1 __first1, _ForwardIterator1 __last1,     _ForwardIterator2 __first2, _ForwardIterator2 __last2,     _BinaryPredicate __comp)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,    typename iterator_traits<_ForwardIterator1>::value_type,    typename iterator_traits<_ForwardIterator2>::value_type>)      __glibcxx_requires_valid_range(__first1, __last1);      __glibcxx_requires_valid_range(__first2, __last2);      return std::__find_end(__first1, __last1, __first2, __last2,     std::__iterator_category(__first1),     std::__iterator_category(__first2),     __comp);    }#ifdef __GXX_EXPERIMENTAL_CXX0X__  /**   *  @brief  Checks that a predicate is true for all the elements   *          of a sequence.   *  @ingroup non_mutating_algorithms   *  @param  __first   An input iterator.   *  @param  __last    An input iterator.   *  @param  __pred    A predicate.   *  @return  True if the check is true, false otherwise.   *   *  Returns true if @p __pred is true for each element in the range   *  @p [__first,__last), and false otherwise.  */  template<typename _InputIterator, typename _Predicate>    inline bool    all_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)    { return __last == std::find_if_not(__first, __last, __pred); }  /**   *  @brief  Checks that a predicate is false for all the elements   *          of a sequence.   *  @ingroup non_mutating_algorithms   *  @param  __first   An input iterator.   *  @param  __last    An input iterator.   *  @param  __pred    A predicate.   *  @return  True if the check is true, false otherwise.   *   *  Returns true if @p __pred is false for each element in the range   *  @p [__first,__last), and false otherwise.  */  template<typename _InputIterator, typename _Predicate>    inline bool    none_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)    { return __last == _GLIBCXX_STD_A::find_if(__first, __last, __pred); }  /**   *  @brief  Checks that a predicate is false for at least an element   *          of a sequence.   *  @ingroup non_mutating_algorithms   *  @param  __first   An input iterator.   *  @param  __last    An input iterator.   *  @param  __pred    A predicate.   *  @return  True if the check is true, false otherwise.   *   *  Returns true if an element exists in the range @p   *  [__first,__last) such that @p __pred is true, and false   *  otherwise.  */  template<typename _InputIterator, typename _Predicate>    inline bool    any_of(_InputIterator __first, _InputIterator __last, _Predicate __pred)    { return !std::none_of(__first, __last, __pred); }  /**   *  @brief  Find the first element in a sequence for which a   *          predicate is false.   *  @ingroup non_mutating_algorithms   *  @param  __first  An input iterator.   *  @param  __last   An input iterator.   *  @param  __pred   A predicate.   *  @return   The first iterator @c i in the range @p [__first,__last)   *  such that @p __pred(*i) is false, or @p __last if no such iterator exists.  */  template<typename _InputIterator, typename _Predicate>    inline _InputIterator    find_if_not(_InputIterator __first, _InputIterator __last,_Predicate __pred)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,      typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      return std::__find_if_not(__first, __last, __pred);    }  /**   *  @brief  Checks whether the sequence is partitioned.   *  @ingroup mutating_algorithms   *  @param  __first  An input iterator.   *  @param  __last   An input iterator.   *  @param  __pred   A predicate.   *  @return  True if the range @p [__first,__last) is partioned by @p __pred,   *  i.e. if all elements that satisfy @p __pred appear before those that   *  do not.  */  template<typename _InputIterator, typename _Predicate>    inline bool    is_partitioned(_InputIterator __first, _InputIterator __last,   _Predicate __pred)    {      __first = std::find_if_not(__first, __last, __pred);      return std::none_of(__first, __last, __pred);    }  /**   *  @brief  Find the partition point of a partitioned range.   *  @ingroup mutating_algorithms   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @param  __pred    A predicate.   *  @return  An iterator @p mid such that @p all_of(__first, mid, __pred)   *           and @p none_of(mid, __last, __pred) are both true.  */  template<typename _ForwardIterator, typename _Predicate>    _ForwardIterator    partition_point(_ForwardIterator __first, _ForwardIterator __last,    _Predicate __pred)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,      typename iterator_traits<_ForwardIterator>::value_type>)      // A specific debug-mode test will be necessary...      __glibcxx_requires_valid_range(__first, __last);      typedef typename iterator_traits<_ForwardIterator>::difference_type_DistanceType;      _DistanceType __len = std::distance(__first, __last);      _DistanceType __half;      _ForwardIterator __middle;      while (__len > 0){  __half = __len >> 1;  __middle = __first;  std::advance(__middle, __half);  if (__pred(*__middle))    {      __first = __middle;      ++__first;      __len = __len - __half - 1;    }  else    __len = __half;}      return __first;    }#endif  /**   *  @brief Copy a sequence, removing elements of a given value.   *  @ingroup mutating_algorithms   *  @param  __first   An input iterator.   *  @param  __last    An input iterator.   *  @param  __result  An output iterator.   *  @param  __value   The value to be removed.   *  @return   An iterator designating the end of the resulting sequence.   *   *  Copies each element in the range @p [__first,__last) not equal   *  to @p __value to the range beginning at @p __result.   *  remove_copy() is stable, so the relative order of elements that   *  are copied is unchanged.  */  template<typename _InputIterator, typename _OutputIterator, typename _Tp>    _OutputIterator    remove_copy(_InputIterator __first, _InputIterator __last,_OutputIterator __result, const _Tp& __value)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,    typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_function_requires(_EqualOpConcept<    typename iterator_traits<_InputIterator>::value_type, _Tp>)      __glibcxx_requires_valid_range(__first, __last);      for (; __first != __last; ++__first)if (!(*__first == __value))  {    *__result = *__first;    ++__result;  }      return __result;    }  /**   *  @brief Copy a sequence, removing elements for which a predicate is true.   *  @ingroup mutating_algorithms   *  @param  __first   An input iterator.   *  @param  __last    An input iterator.   *  @param  __result  An output iterator.   *  @param  __pred    A predicate.   *  @return   An iterator designating the end of the resulting sequence.   *   *  Copies each element in the range @p [__first,__last) for which   *  @p __pred returns false to the range beginning at @p __result.   *   *  remove_copy_if() is stable, so the relative order of elements that are   *  copied is unchanged.  */  template<typename _InputIterator, typename _OutputIterator,   typename _Predicate>    _OutputIterator    remove_copy_if(_InputIterator __first, _InputIterator __last,   _OutputIterator __result, _Predicate __pred)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,    typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,    typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      for (; __first != __last; ++__first)if (!bool(__pred(*__first)))  {    *__result = *__first;    ++__result;  }      return __result;    }#ifdef __GXX_EXPERIMENTAL_CXX0X__  /**   *  @brief Copy the elements of a sequence for which a predicate is true.   *  @ingroup mutating_algorithms   *  @param  __first   An input iterator.   *  @param  __last    An input iterator.   *  @param  __result  An output iterator.   *  @param  __pred    A predicate.   *  @return   An iterator designating the end of the resulting sequence.   *   *  Copies each element in the range @p [__first,__last) for which   *  @p __pred returns true to the range beginning at @p __result.   *   *  copy_if() is stable, so the relative order of elements that are   *  copied is unchanged.  */  template<typename _InputIterator, typename _OutputIterator,   typename _Predicate>    _OutputIterator    copy_if(_InputIterator __first, _InputIterator __last,    _OutputIterator __result, _Predicate __pred)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,    typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,    typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      for (; __first != __last; ++__first)if (__pred(*__first))  {    *__result = *__first;    ++__result;  }      return __result;    }  template<typename _InputIterator, typename _Size, typename _OutputIterator>    _OutputIterator    __copy_n(_InputIterator __first, _Size __n,     _OutputIterator __result, input_iterator_tag)    {      if (__n > 0){  while (true)    {      *__result = *__first;      ++__result;      if (--__n > 0)++__first;      elsebreak;    }}      return __result;    }  template<typename _RandomAccessIterator, typename _Size,   typename _OutputIterator>    inline _OutputIterator    __copy_n(_RandomAccessIterator __first, _Size __n,     _OutputIterator __result, random_access_iterator_tag)    { return std::copy(__first, __first + __n, __result); }  /**   *  @brief Copies the range [first,first+n) into [result,result+n).   *  @ingroup mutating_algorithms   *  @param  __first  An input iterator.   *  @param  __n      The number of elements to copy.   *  @param  __result An output iterator.   *  @return  result+n.   *   *  This inline function will boil down to a call to @c memmove whenever   *  possible.  Failing that, if random access iterators are passed, then the   *  loop count will be known (and therefore a candidate for compiler   *  optimizations such as unrolling).  */  template<typename _InputIterator, typename _Size, typename _OutputIterator>    inline _OutputIterator    copy_n(_InputIterator __first, _Size __n, _OutputIterator __result)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,    typename iterator_traits<_InputIterator>::value_type>)      return std::__copy_n(__first, __n, __result,   std::__iterator_category(__first));    }  /**   *  @brief Copy the elements of a sequence to separate output sequences   *         depending on the truth value of a predicate.   *  @ingroup mutating_algorithms   *  @param  __first   An input iterator.   *  @param  __last    An input iterator.   *  @param  __out_true   An output iterator.   *  @param  __out_false  An output iterator.   *  @param  __pred    A predicate.   *  @return   A pair designating the ends of the resulting sequences.   *   *  Copies each element in the range @p [__first,__last) for which   *  @p __pred returns true to the range beginning at @p out_true   *  and each element for which @p __pred returns false to @p __out_false.  */  template<typename _InputIterator, typename _OutputIterator1,   typename _OutputIterator2, typename _Predicate>    pair<_OutputIterator1, _OutputIterator2>    partition_copy(_InputIterator __first, _InputIterator __last,   _OutputIterator1 __out_true, _OutputIterator2 __out_false,   _Predicate __pred)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator1,    typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator2,    typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,    typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);            for (; __first != __last; ++__first)if (__pred(*__first))  {    *__out_true = *__first;    ++__out_true;  }else  {    *__out_false = *__first;    ++__out_false;  }      return pair<_OutputIterator1, _OutputIterator2>(__out_true, __out_false);    }#endif  /**   *  @brief Remove elements from a sequence.   *  @ingroup mutating_algorithms   *  @param  __first  An input iterator.   *  @param  __last   An input iterator.   *  @param  __value  The value to be removed.   *  @return   An iterator designating the end of the resulting sequence.   *   *  All elements equal to @p __value are removed from the range   *  @p [__first,__last).   *   *  remove() is stable, so the relative order of elements that are   *  not removed is unchanged.   *   *  Elements between the end of the resulting sequence and @p __last   *  are still present, but their value is unspecified.  */  template<typename _ForwardIterator, typename _Tp>    _ForwardIterator    remove(_ForwardIterator __first, _ForwardIterator __last,   const _Tp& __value)    {      // concept requirements      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<  _ForwardIterator>)      __glibcxx_function_requires(_EqualOpConcept<    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)      __glibcxx_requires_valid_range(__first, __last);      __first = _GLIBCXX_STD_A::find(__first, __last, __value);      if(__first == __last)        return __first;      _ForwardIterator __result = __first;      ++__first;      for(; __first != __last; ++__first)        if(!(*__first == __value))          {            *__result = _GLIBCXX_MOVE(*__first);            ++__result;          }      return __result;    }  /**   *  @brief Remove elements from a sequence using a predicate.   *  @ingroup mutating_algorithms   *  @param  __first  A forward iterator.   *  @param  __last   A forward iterator.   *  @param  __pred   A predicate.   *  @return   An iterator designating the end of the resulting sequence.   *   *  All elements for which @p __pred returns true are removed from the range   *  @p [__first,__last).   *   *  remove_if() is stable, so the relative order of elements that are   *  not removed is unchanged.   *   *  Elements between the end of the resulting sequence and @p __last   *  are still present, but their value is unspecified.  */  template<typename _ForwardIterator, typename _Predicate>    _ForwardIterator    remove_if(_ForwardIterator __first, _ForwardIterator __last,      _Predicate __pred)    {      // concept requirements      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<  _ForwardIterator>)      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      __first = _GLIBCXX_STD_A::find_if(__first, __last, __pred);      if(__first == __last)        return __first;      _ForwardIterator __result = __first;      ++__first;      for(; __first != __last; ++__first)        if(!bool(__pred(*__first)))          {            *__result = _GLIBCXX_MOVE(*__first);            ++__result;          }      return __result;    }  /**   *  @brief Remove consecutive duplicate values from a sequence.   *  @ingroup mutating_algorithms   *  @param  __first  A forward iterator.   *  @param  __last   A forward iterator.   *  @return  An iterator designating the end of the resulting sequence.   *   *  Removes all but the first element from each group of consecutive   *  values that compare equal.   *  unique() is stable, so the relative order of elements that are   *  not removed is unchanged.   *  Elements between the end of the resulting sequence and @p __last   *  are still present, but their value is unspecified.  */  template<typename _ForwardIterator>    _ForwardIterator    unique(_ForwardIterator __first, _ForwardIterator __last)    {      // concept requirements      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<  _ForwardIterator>)      __glibcxx_function_requires(_EqualityComparableConcept<     typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      // Skip the beginning, if already unique.      __first = _GLIBCXX_STD_A::adjacent_find(__first, __last);      if (__first == __last)return __last;      // Do the real copy work.      _ForwardIterator __dest = __first;      ++__first;      while (++__first != __last)if (!(*__dest == *__first))  *++__dest = _GLIBCXX_MOVE(*__first);      return ++__dest;    }  /**   *  @brief Remove consecutive values from a sequence using a predicate.   *  @ingroup mutating_algorithms   *  @param  __first        A forward iterator.   *  @param  __last         A forward iterator.   *  @param  __binary_pred  A binary predicate.   *  @return  An iterator designating the end of the resulting sequence.   *   *  Removes all but the first element from each group of consecutive   *  values for which @p __binary_pred returns true.   *  unique() is stable, so the relative order of elements that are   *  not removed is unchanged.   *  Elements between the end of the resulting sequence and @p __last   *  are still present, but their value is unspecified.  */  template<typename _ForwardIterator, typename _BinaryPredicate>    _ForwardIterator    unique(_ForwardIterator __first, _ForwardIterator __last,           _BinaryPredicate __binary_pred)    {      // concept requirements      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<  _ForwardIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,typename iterator_traits<_ForwardIterator>::value_type,typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      // Skip the beginning, if already unique.      __first = _GLIBCXX_STD_A::adjacent_find(__first, __last, __binary_pred);      if (__first == __last)return __last;      // Do the real copy work.      _ForwardIterator __dest = __first;      ++__first;      while (++__first != __last)if (!bool(__binary_pred(*__dest, *__first)))  *++__dest = _GLIBCXX_MOVE(*__first);      return ++__dest;    }  /**   *  This is an uglified unique_copy(_InputIterator, _InputIterator,   *                                  _OutputIterator)   *  overloaded for forward iterators and output iterator as result.  */  template<typename _ForwardIterator, typename _OutputIterator>    _OutputIterator    __unique_copy(_ForwardIterator __first, _ForwardIterator __last,  _OutputIterator __result,  forward_iterator_tag, output_iterator_tag)    {      // concept requirements -- taken care of in dispatching function      _ForwardIterator __next = __first;      *__result = *__first;      while (++__next != __last)if (!(*__first == *__next))  {    __first = __next;    *++__result = *__first;  }      return ++__result;    }  /**   *  This is an uglified unique_copy(_InputIterator, _InputIterator,   *                                  _OutputIterator)   *  overloaded for input iterators and output iterator as result.  */  template<typename _InputIterator, typename _OutputIterator>    _OutputIterator    __unique_copy(_InputIterator __first, _InputIterator __last,  _OutputIterator __result,  input_iterator_tag, output_iterator_tag)    {      // concept requirements -- taken care of in dispatching function      typename iterator_traits<_InputIterator>::value_type __value = *__first;      *__result = __value;      while (++__first != __last)if (!(__value == *__first))  {    __value = *__first;    *++__result = __value;  }      return ++__result;    }  /**   *  This is an uglified unique_copy(_InputIterator, _InputIterator,   *                                  _OutputIterator)   *  overloaded for input iterators and forward iterator as result.  */  template<typename _InputIterator, typename _ForwardIterator>    _ForwardIterator    __unique_copy(_InputIterator __first, _InputIterator __last,  _ForwardIterator __result,  input_iterator_tag, forward_iterator_tag)    {      // concept requirements -- taken care of in dispatching function      *__result = *__first;      while (++__first != __last)if (!(*__result == *__first))  *++__result = *__first;      return ++__result;    }  /**   *  This is an uglified   *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,   *              _BinaryPredicate)   *  overloaded for forward iterators and output iterator as result.  */  template<typename _ForwardIterator, typename _OutputIterator,   typename _BinaryPredicate>    _OutputIterator    __unique_copy(_ForwardIterator __first, _ForwardIterator __last,  _OutputIterator __result, _BinaryPredicate __binary_pred,  forward_iterator_tag, output_iterator_tag)    {      // concept requirements -- iterators already checked      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,  typename iterator_traits<_ForwardIterator>::value_type,  typename iterator_traits<_ForwardIterator>::value_type>)      _ForwardIterator __next = __first;      *__result = *__first;      while (++__next != __last)if (!bool(__binary_pred(*__first, *__next)))  {    __first = __next;    *++__result = *__first;  }      return ++__result;    }  /**   *  This is an uglified   *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,   *              _BinaryPredicate)   *  overloaded for input iterators and output iterator as result.  */  template<typename _InputIterator, typename _OutputIterator,   typename _BinaryPredicate>    _OutputIterator    __unique_copy(_InputIterator __first, _InputIterator __last,  _OutputIterator __result, _BinaryPredicate __binary_pred,  input_iterator_tag, output_iterator_tag)    {      // concept requirements -- iterators already checked      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,  typename iterator_traits<_InputIterator>::value_type,  typename iterator_traits<_InputIterator>::value_type>)      typename iterator_traits<_InputIterator>::value_type __value = *__first;      *__result = __value;      while (++__first != __last)if (!bool(__binary_pred(__value, *__first)))  {    __value = *__first;    *++__result = __value;  }      return ++__result;    }  /**   *  This is an uglified   *  unique_copy(_InputIterator, _InputIterator, _OutputIterator,   *              _BinaryPredicate)   *  overloaded for input iterators and forward iterator as result.  */  template<typename _InputIterator, typename _ForwardIterator,   typename _BinaryPredicate>    _ForwardIterator    __unique_copy(_InputIterator __first, _InputIterator __last,  _ForwardIterator __result, _BinaryPredicate __binary_pred,  input_iterator_tag, forward_iterator_tag)    {      // concept requirements -- iterators already checked      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,  typename iterator_traits<_ForwardIterator>::value_type,  typename iterator_traits<_InputIterator>::value_type>)      *__result = *__first;      while (++__first != __last)if (!bool(__binary_pred(*__result, *__first)))  *++__result = *__first;      return ++__result;    }  /**   *  This is an uglified reverse(_BidirectionalIterator,   *                              _BidirectionalIterator)   *  overloaded for bidirectional iterators.  */  template<typename _BidirectionalIterator>    void    __reverse(_BidirectionalIterator __first, _BidirectionalIterator __last,      bidirectional_iterator_tag)    {      while (true)if (__first == __last || __first == --__last)  return;else  {    std::iter_swap(__first, __last);    ++__first;  }    }  /**   *  This is an uglified reverse(_BidirectionalIterator,   *                              _BidirectionalIterator)   *  overloaded for random access iterators.  */  template<typename _RandomAccessIterator>    void    __reverse(_RandomAccessIterator __first, _RandomAccessIterator __last,      random_access_iterator_tag)    {      if (__first == __last)return;      --__last;      while (__first < __last){  std::iter_swap(__first, __last);  ++__first;  --__last;}    }  /**   *  @brief Reverse a sequence.   *  @ingroup mutating_algorithms   *  @param  __first  A bidirectional iterator.   *  @param  __last   A bidirectional iterator.   *  @return   reverse() returns no value.   *   *  Reverses the order of the elements in the range @p [__first,__last),   *  so that the first element becomes the last etc.   *  For every @c i such that @p 0<=i<=(__last-__first)/2), @p reverse()   *  swaps @p *(__first+i) and @p *(__last-(i+1))  */  template<typename _BidirectionalIterator>    inline void    reverse(_BidirectionalIterator __first, _BidirectionalIterator __last)    {      // concept requirements      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<  _BidirectionalIterator>)      __glibcxx_requires_valid_range(__first, __last);      std::__reverse(__first, __last, std::__iterator_category(__first));    }  /**   *  @brief Copy a sequence, reversing its elements.   *  @ingroup mutating_algorithms   *  @param  __first   A bidirectional iterator.   *  @param  __last    A bidirectional iterator.   *  @param  __result  An output iterator.   *  @return  An iterator designating the end of the resulting sequence.   *   *  Copies the elements in the range @p [__first,__last) to the   *  range @p [__result,__result+(__last-__first)) such that the   *  order of the elements is reversed.  For every @c i such that @p   *  0<=i<=(__last-__first), @p reverse_copy() performs the   *  assignment @p *(__result+(__last-__first)-i) = *(__first+i).   *  The ranges @p [__first,__last) and @p   *  [__result,__result+(__last-__first)) must not overlap.  */  template<typename _BidirectionalIterator, typename _OutputIterator>    _OutputIterator    reverse_copy(_BidirectionalIterator __first, _BidirectionalIterator __last, _OutputIterator __result)    {      // concept requirements      __glibcxx_function_requires(_BidirectionalIteratorConcept<  _BidirectionalIterator>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,typename iterator_traits<_BidirectionalIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      while (__first != __last){  --__last;  *__result = *__last;  ++__result;}      return __result;    }  /**   *  This is a helper function for the rotate algorithm specialized on RAIs.   *  It returns the greatest common divisor of two integer values.  */  template<typename _EuclideanRingElement>    _EuclideanRingElement    __gcd(_EuclideanRingElement __m, _EuclideanRingElement __n)    {      while (__n != 0){  _EuclideanRingElement __t = __m % __n;  __m = __n;  __n = __t;}      return __m;    }  /// This is a helper function for the rotate algorithm.  template<typename _ForwardIterator>    void    __rotate(_ForwardIterator __first,     _ForwardIterator __middle,     _ForwardIterator __last,     forward_iterator_tag)    {      if (__first == __middle || __last  == __middle)return;      _ForwardIterator __first2 = __middle;      do{  std::iter_swap(__first, __first2);  ++__first;  ++__first2;  if (__first == __middle)    __middle = __first2;}      while (__first2 != __last);      __first2 = __middle;      while (__first2 != __last){  std::iter_swap(__first, __first2);  ++__first;  ++__first2;  if (__first == __middle)    __middle = __first2;  else if (__first2 == __last)    __first2 = __middle;}    }   /// This is a helper function for the rotate algorithm.  template<typename _BidirectionalIterator>    void    __rotate(_BidirectionalIterator __first,     _BidirectionalIterator __middle,     _BidirectionalIterator __last,      bidirectional_iterator_tag)    {      // concept requirements      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<  _BidirectionalIterator>)      if (__first == __middle || __last  == __middle)return;      std::__reverse(__first,  __middle, bidirectional_iterator_tag());      std::__reverse(__middle, __last,   bidirectional_iterator_tag());      while (__first != __middle && __middle != __last){  std::iter_swap(__first, --__last);  ++__first;}      if (__first == __middle)std::__reverse(__middle, __last,   bidirectional_iterator_tag());      elsestd::__reverse(__first,  __middle, bidirectional_iterator_tag());    }  /// This is a helper function for the rotate algorithm.  template<typename _RandomAccessIterator>    void    __rotate(_RandomAccessIterator __first,     _RandomAccessIterator __middle,     _RandomAccessIterator __last,     random_access_iterator_tag)    {      // concept requirements      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<  _RandomAccessIterator>)      if (__first == __middle || __last  == __middle)return;      typedef typename iterator_traits<_RandomAccessIterator>::difference_type_Distance;      typedef typename iterator_traits<_RandomAccessIterator>::value_type_ValueType;      _Distance __n = __last   - __first;      _Distance __k = __middle - __first;      if (__k == __n - __k){  std::swap_ranges(__first, __middle, __middle);  return;}      _RandomAccessIterator __p = __first;      for (;;){  if (__k < __n - __k)    {      if (__is_pod(_ValueType) && __k == 1){  _ValueType __t = _GLIBCXX_MOVE(*__p);  _GLIBCXX_MOVE3(__p + 1, __p + __n, __p);  *(__p + __n - 1) = _GLIBCXX_MOVE(__t);  return;}      _RandomAccessIterator __q = __p + __k;      for (_Distance __i = 0; __i < __n - __k; ++ __i){  std::iter_swap(__p, __q);  ++__p;  ++__q;}      __n %= __k;      if (__n == 0)return;      std::swap(__n, __k);      __k = __n - __k;    }  else    {      __k = __n - __k;      if (__is_pod(_ValueType) && __k == 1){  _ValueType __t = _GLIBCXX_MOVE(*(__p + __n - 1));  _GLIBCXX_MOVE_BACKWARD3(__p, __p + __n - 1, __p + __n);  *__p = _GLIBCXX_MOVE(__t);  return;}      _RandomAccessIterator __q = __p + __n;      __p = __q - __k;      for (_Distance __i = 0; __i < __n - __k; ++ __i){  --__p;  --__q;  std::iter_swap(__p, __q);}      __n %= __k;      if (__n == 0)return;      std::swap(__n, __k);    }}    }  /**   *  @brief Rotate the elements of a sequence.   *  @ingroup mutating_algorithms   *  @param  __first   A forward iterator.   *  @param  __middle  A forward iterator.   *  @param  __last    A forward iterator.   *  @return  Nothing.   *   *  Rotates the elements of the range @p [__first,__last) by    *  @p (__middle - __first) positions so that the element at @p __middle   *  is moved to @p __first, the element at @p __middle+1 is moved to   *  @p __first+1 and so on for each element in the range   *  @p [__first,__last).   *   *  This effectively swaps the ranges @p [__first,__middle) and   *  @p [__middle,__last).   *   *  Performs   *   @p *(__first+(n+(__last-__middle))%(__last-__first))=*(__first+n)   *  for each @p n in the range @p [0,__last-__first).  */  template<typename _ForwardIterator>    inline void    rotate(_ForwardIterator __first, _ForwardIterator __middle,   _ForwardIterator __last)    {      // concept requirements      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<  _ForwardIterator>)      __glibcxx_requires_valid_range(__first, __middle);      __glibcxx_requires_valid_range(__middle, __last);      typedef typename iterator_traits<_ForwardIterator>::iterator_category_IterType;      std::__rotate(__first, __middle, __last, _IterType());    }  /**   *  @brief Copy a sequence, rotating its elements.   *  @ingroup mutating_algorithms   *  @param  __first   A forward iterator.   *  @param  __middle  A forward iterator.   *  @param  __last    A forward iterator.   *  @param  __result  An output iterator.   *  @return   An iterator designating the end of the resulting sequence.   *   *  Copies the elements of the range @p [__first,__last) to the   *  range beginning at @result, rotating the copied elements by    *  @p (__middle-__first) positions so that the element at @p __middle   *  is moved to @p __result, the element at @p __middle+1 is moved   *  to @p __result+1 and so on for each element in the range @p   *  [__first,__last).   *   *  Performs    *  @p *(__result+(n+(__last-__middle))%(__last-__first))=*(__first+n)   *  for each @p n in the range @p [0,__last-__first).  */  template<typename _ForwardIterator, typename _OutputIterator>    _OutputIterator    rotate_copy(_ForwardIterator __first, _ForwardIterator __middle,                _ForwardIterator __last, _OutputIterator __result)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __middle);      __glibcxx_requires_valid_range(__middle, __last);      return std::copy(__first, __middle,                       std::copy(__middle, __last, __result));    }  /// This is a helper function...  template<typename _ForwardIterator, typename _Predicate>    _ForwardIterator    __partition(_ForwardIterator __first, _ForwardIterator __last,_Predicate __pred, forward_iterator_tag)    {      if (__first == __last)return __first;      while (__pred(*__first))if (++__first == __last)  return __first;      _ForwardIterator __next = __first;      while (++__next != __last)if (__pred(*__next))  {    std::iter_swap(__first, __next);    ++__first;  }      return __first;    }  /// This is a helper function...  template<typename _BidirectionalIterator, typename _Predicate>    _BidirectionalIterator    __partition(_BidirectionalIterator __first, _BidirectionalIterator __last,_Predicate __pred, bidirectional_iterator_tag)    {      while (true){  while (true)    if (__first == __last)      return __first;    else if (__pred(*__first))      ++__first;    else      break;  --__last;  while (true)    if (__first == __last)      return __first;    else if (!bool(__pred(*__last)))      --__last;    else      break;  std::iter_swap(__first, __last);  ++__first;}    }  // partition  /// This is a helper function...  /// Requires __len != 0 and !__pred(*__first),  /// same as __stable_partition_adaptive.  template<typename _ForwardIterator, typename _Predicate, typename _Distance>    _ForwardIterator    __inplace_stable_partition(_ForwardIterator __first,       _Predicate __pred, _Distance __len)    {      if (__len == 1)return __first;      _ForwardIterator __middle = __first;      std::advance(__middle, __len / 2);      _ForwardIterator __left_split =std::__inplace_stable_partition(__first, __pred, __len / 2);      // Advance past true-predicate values to satisfy this      // function's preconditions.      _Distance __right_len = __len - __len / 2;      _ForwardIterator __right_split =std::__find_if_not_n(__middle, __right_len, __pred);      if (__right_len)__right_split = std::__inplace_stable_partition(__middle,__pred,__right_len);      std::rotate(__left_split, __middle, __right_split);      std::advance(__left_split, std::distance(__middle, __right_split));      return __left_split;    }  /// This is a helper function...  /// Requires __first != __last and !__pred(*__first)  /// and __len == distance(__first, __last).  ///  /// !__pred(*__first) allows us to guarantee that we don't  /// move-assign an element onto itself.  template<typename _ForwardIterator, typename _Pointer, typename _Predicate,   typename _Distance>    _ForwardIterator    __stable_partition_adaptive(_ForwardIterator __first,_ForwardIterator __last,_Predicate __pred, _Distance __len,_Pointer __buffer,_Distance __buffer_size)    {      if (__len <= __buffer_size){  _ForwardIterator __result1 = __first;  _Pointer __result2 = __buffer;  // The precondition guarantees that !__pred(*__first), so  // move that element to the buffer before starting the loop.  // This ensures that we only call __pred once per element.  *__result2 = _GLIBCXX_MOVE(*__first);  ++__result2;  ++__first;  for (; __first != __last; ++__first)    if (__pred(*__first))      {*__result1 = _GLIBCXX_MOVE(*__first);++__result1;      }    else      {*__result2 = _GLIBCXX_MOVE(*__first);++__result2;      }  _GLIBCXX_MOVE3(__buffer, __result2, __result1);  return __result1;}      else{  _ForwardIterator __middle = __first;  std::advance(__middle, __len / 2);  _ForwardIterator __left_split =    std::__stable_partition_adaptive(__first, __middle, __pred,     __len / 2, __buffer,     __buffer_size);  // Advance past true-predicate values to satisfy this  // function's preconditions.  _Distance __right_len = __len - __len / 2;  _ForwardIterator __right_split =    std::__find_if_not_n(__middle, __right_len, __pred);  if (__right_len)    __right_split =      std::__stable_partition_adaptive(__right_split, __last, __pred,       __right_len,       __buffer, __buffer_size);  std::rotate(__left_split, __middle, __right_split);  std::advance(__left_split, std::distance(__middle, __right_split));  return __left_split;}    }  /**   *  @brief Move elements for which a predicate is true to the beginning   *         of a sequence, preserving relative ordering.   *  @ingroup mutating_algorithms   *  @param  __first   A forward iterator.   *  @param  __last    A forward iterator.   *  @param  __pred    A predicate functor.   *  @return  An iterator @p middle such that @p __pred(i) is true for each   *  iterator @p i in the range @p [first,middle) and false for each @p i   *  in the range @p [middle,last).   *   *  Performs the same function as @p partition() with the additional   *  guarantee that the relative ordering of elements in each group is   *  preserved, so any two elements @p x and @p y in the range   *  @p [__first,__last) such that @p __pred(x)==__pred(y) will have the same   *  relative ordering after calling @p stable_partition().  */  template<typename _ForwardIterator, typename _Predicate>    _ForwardIterator    stable_partition(_ForwardIterator __first, _ForwardIterator __last,     _Predicate __pred)    {      // concept requirements      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<  _ForwardIterator>)      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      __first = std::__find_if_not(__first, __last, __pred);      if (__first == __last)return __first;      else{  typedef typename iterator_traits<_ForwardIterator>::value_type    _ValueType;  typedef typename iterator_traits<_ForwardIterator>::difference_type    _DistanceType;  _Temporary_buffer<_ForwardIterator, _ValueType> __buf(__first,__last);if (__buf.size() > 0)  return    std::__stable_partition_adaptive(__first, __last, __pred,  _DistanceType(__buf.requested_size()),  __buf.begin(),  _DistanceType(__buf.size()));else  return    std::__inplace_stable_partition(__first, __pred, _DistanceType(__buf.requested_size()));}    }  /// This is a helper function for the sort routines.  template<typename _RandomAccessIterator>    void    __heap_select(_RandomAccessIterator __first,  _RandomAccessIterator __middle,  _RandomAccessIterator __last)    {      std::make_heap(__first, __middle);      for (_RandomAccessIterator __i = __middle; __i < __last; ++__i)if (*__i < *__first)  std::__pop_heap(__first, __middle, __i);    }  /// This is a helper function for the sort routines.  template<typename _RandomAccessIterator, typename _Compare>    void    __heap_select(_RandomAccessIterator __first,  _RandomAccessIterator __middle,  _RandomAccessIterator __last, _Compare __comp)    {      std::make_heap(__first, __middle, __comp);      for (_RandomAccessIterator __i = __middle; __i < __last; ++__i)if (__comp(*__i, *__first))  std::__pop_heap(__first, __middle, __i, __comp);    }  // partial_sort  /**   *  @brief Copy the smallest elements of a sequence.   *  @ingroup sorting_algorithms   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @param  __result_first   A random-access iterator.   *  @param  __result_last    Another random-access iterator.   *  @return   An iterator indicating the end of the resulting sequence.   *   *  Copies and sorts the smallest N values from the range @p [__first,__last)   *  to the range beginning at @p __result_first, where the number of   *  elements to be copied, @p N, is the smaller of @p (__last-__first) and   *  @p (__result_last-__result_first).   *  After the sort if @e i and @e j are iterators in the range   *  @p [__result_first,__result_first+N) such that i precedes j then   *  *j<*i is false.   *  The value returned is @p __result_first+N.  */  template<typename _InputIterator, typename _RandomAccessIterator>    _RandomAccessIterator    partial_sort_copy(_InputIterator __first, _InputIterator __last,      _RandomAccessIterator __result_first,      _RandomAccessIterator __result_last)    {      typedef typename iterator_traits<_InputIterator>::value_type_InputValueType;      typedef typename iterator_traits<_RandomAccessIterator>::value_type_OutputValueType;      typedef typename iterator_traits<_RandomAccessIterator>::difference_type_DistanceType;      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_ConvertibleConcept<_InputValueType,  _OutputValueType>)      __glibcxx_function_requires(_LessThanOpConcept<_InputValueType,                     _OutputValueType>)      __glibcxx_function_requires(_LessThanComparableConcept<_OutputValueType>)      __glibcxx_requires_valid_range(__first, __last);      __glibcxx_requires_valid_range(__result_first, __result_last);      if (__result_first == __result_last)return __result_last;      _RandomAccessIterator __result_real_last = __result_first;      while(__first != __last && __result_real_last != __result_last){  *__result_real_last = *__first;  ++__result_real_last;  ++__first;}      std::make_heap(__result_first, __result_real_last);      while (__first != __last){  if (*__first < *__result_first)    std::__adjust_heap(__result_first, _DistanceType(0),       _DistanceType(__result_real_last     - __result_first),       _InputValueType(*__first));  ++__first;}      std::sort_heap(__result_first, __result_real_last);      return __result_real_last;    }  /**   *  @brief Copy the smallest elements of a sequence using a predicate for   *         comparison.   *  @ingroup sorting_algorithms   *  @param  __first   An input iterator.   *  @param  __last    Another input iterator.   *  @param  __result_first   A random-access iterator.   *  @param  __result_last    Another random-access iterator.   *  @param  __comp    A comparison functor.   *  @return   An iterator indicating the end of the resulting sequence.   *   *  Copies and sorts the smallest N values from the range @p [__first,__last)   *  to the range beginning at @p result_first, where the number of   *  elements to be copied, @p N, is the smaller of @p (__last-__first) and   *  @p (__result_last-__result_first).   *  After the sort if @e i and @e j are iterators in the range   *  @p [__result_first,__result_first+N) such that i precedes j then   *  @p __comp(*j,*i) is false.   *  The value returned is @p __result_first+N.  */  template<typename _InputIterator, typename _RandomAccessIterator, typename _Compare>    _RandomAccessIterator    partial_sort_copy(_InputIterator __first, _InputIterator __last,      _RandomAccessIterator __result_first,      _RandomAccessIterator __result_last,      _Compare __comp)    {      typedef typename iterator_traits<_InputIterator>::value_type_InputValueType;      typedef typename iterator_traits<_RandomAccessIterator>::value_type_OutputValueType;      typedef typename iterator_traits<_RandomAccessIterator>::difference_type_DistanceType;      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<  _RandomAccessIterator>)      __glibcxx_function_requires(_ConvertibleConcept<_InputValueType,  _OutputValueType>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _InputValueType, _OutputValueType>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _OutputValueType, _OutputValueType>)      __glibcxx_requires_valid_range(__first, __last);      __glibcxx_requires_valid_range(__result_first, __result_last);      if (__result_first == __result_last)return __result_last;      _RandomAccessIterator __result_real_last = __result_first;      while(__first != __last && __result_real_last != __result_last){  *__result_real_last = *__first;  ++__result_real_last;  ++__first;}      std::make_heap(__result_first, __result_real_last, __comp);      while (__first != __last){  if (__comp(*__first, *__result_first))    std::__adjust_heap(__result_first, _DistanceType(0),       _DistanceType(__result_real_last     - __result_first),       _InputValueType(*__first),       __comp);  ++__first;}      std::sort_heap(__result_first, __result_real_last, __comp);      return __result_real_last;    }  /// This is a helper function for the sort routine.  template<typename _RandomAccessIterator>    void    __unguarded_linear_insert(_RandomAccessIterator __last)    {      typename iterator_traits<_RandomAccessIterator>::value_type__val = _GLIBCXX_MOVE(*__last);      _RandomAccessIterator __next = __last;      --__next;      while (__val < *__next){  *__last = _GLIBCXX_MOVE(*__next);  __last = __next;  --__next;}      *__last = _GLIBCXX_MOVE(__val);    }  /// This is a helper function for the sort routine.  template<typename _RandomAccessIterator, typename _Compare>    void    __unguarded_linear_insert(_RandomAccessIterator __last,      _Compare __comp)    {      typename iterator_traits<_RandomAccessIterator>::value_type__val = _GLIBCXX_MOVE(*__last);      _RandomAccessIterator __next = __last;      --__next;      while (__comp(__val, *__next)){  *__last = _GLIBCXX_MOVE(*__next);  __last = __next;  --__next;}      *__last = _GLIBCXX_MOVE(__val);    }  /// This is a helper function for the sort routine.  template<typename _RandomAccessIterator>    void    __insertion_sort(_RandomAccessIterator __first,     _RandomAccessIterator __last)    {      if (__first == __last)return;      for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i){  if (*__i < *__first)    {      typename iterator_traits<_RandomAccessIterator>::value_type__val = _GLIBCXX_MOVE(*__i);      _GLIBCXX_MOVE_BACKWARD3(__first, __i, __i + 1);      *__first = _GLIBCXX_MOVE(__val);    }  else    std::__unguarded_linear_insert(__i);}    }  /// This is a helper function for the sort routine.  template<typename _RandomAccessIterator, typename _Compare>    void    __insertion_sort(_RandomAccessIterator __first,     _RandomAccessIterator __last, _Compare __comp)    {      if (__first == __last) return;      for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i){  if (__comp(*__i, *__first))    {      typename iterator_traits<_RandomAccessIterator>::value_type__val = _GLIBCXX_MOVE(*__i);      _GLIBCXX_MOVE_BACKWARD3(__first, __i, __i + 1);      *__first = _GLIBCXX_MOVE(__val);    }  else    std::__unguarded_linear_insert(__i, __comp);}    }  /// This is a helper function for the sort routine.  template<typename _RandomAccessIterator>    inline void    __unguarded_insertion_sort(_RandomAccessIterator __first,       _RandomAccessIterator __last)    {      typedef typename iterator_traits<_RandomAccessIterator>::value_type_ValueType;      for (_RandomAccessIterator __i = __first; __i != __last; ++__i)std::__unguarded_linear_insert(__i);    }  /// This is a helper function for the sort routine.  template<typename _RandomAccessIterator, typename _Compare>    inline void    __unguarded_insertion_sort(_RandomAccessIterator __first,       _RandomAccessIterator __last, _Compare __comp)    {      typedef typename iterator_traits<_RandomAccessIterator>::value_type_ValueType;      for (_RandomAccessIterator __i = __first; __i != __last; ++__i)std::__unguarded_linear_insert(__i, __comp);    }  /**   *  @doctodo   *  This controls some aspect of the sort routines.  */  enum { _S_threshold = 16 };  /// This is a helper function for the sort routine.  template<typename _RandomAccessIterator>    void    __final_insertion_sort(_RandomAccessIterator __first,   _RandomAccessIterator __last)    {      if (__last - __first > int(_S_threshold)){  std::__insertion_sort(__first, __first + int(_S_threshold));  std::__unguarded_insertion_sort(__first + int(_S_threshold), __last);}      elsestd::__insertion_sort(__first, __last);    }  /// This is a helper function for the sort routine.  template<typename _RandomAccessIterator, typename _Compare>    void    __final_insertion_sort(_RandomAccessIterator __first,   _RandomAccessIterator __last, _Compare __comp)    {      if (__last - __first > int(_S_threshold)){  std::__insertion_sort(__first, __first + int(_S_threshold), __comp);  std::__unguarded_insertion_sort(__first + int(_S_threshold), __last,  __comp);}      elsestd::__insertion_sort(__first, __last, __comp);    }  /// This is a helper function...  template<typename _RandomAccessIterator, typename _Tp>    _RandomAccessIterator    __unguarded_partition(_RandomAccessIterator __first,  _RandomAccessIterator __last, const _Tp& __pivot)    {      while (true){  while (*__first < __pivot)    ++__first;  --__last;  while (__pivot < *__last)    --__last;  if (!(__first < __last))    return __first;  std::iter_swap(__first, __last);  ++__first;}    }  /// This is a helper function...  template<typename _RandomAccessIterator, typename _Tp, typename _Compare>    _RandomAccessIterator    __unguarded_partition(_RandomAccessIterator __first,  _RandomAccessIterator __last,  const _Tp& __pivot, _Compare __comp)    {      while (true){  while (__comp(*__first, __pivot))    ++__first;  --__last;  while (__comp(__pivot, *__last))    --__last;  if (!(__first < __last))    return __first;  std::iter_swap(__first, __last);  ++__first;}    }  /// This is a helper function...  template<typename _RandomAccessIterator>    inline _RandomAccessIterator    __unguarded_partition_pivot(_RandomAccessIterator __first,_RandomAccessIterator __last)    {      _RandomAccessIterator __mid = __first + (__last - __first) / 2;      std::__move_median_first(__first, __mid, (__last - 1));      return std::__unguarded_partition(__first + 1, __last, *__first);    }  /// This is a helper function...  template<typename _RandomAccessIterator, typename _Compare>    inline _RandomAccessIterator    __unguarded_partition_pivot(_RandomAccessIterator __first,_RandomAccessIterator __last, _Compare __comp)    {      _RandomAccessIterator __mid = __first + (__last - __first) / 2;      std::__move_median_first(__first, __mid, (__last - 1), __comp);      return std::__unguarded_partition(__first + 1, __last, *__first, __comp);    }  /// This is a helper function for the sort routine.  template<typename _RandomAccessIterator, typename _Size>    void    __introsort_loop(_RandomAccessIterator __first,     _RandomAccessIterator __last,     _Size __depth_limit)    {      while (__last - __first > int(_S_threshold)){  if (__depth_limit == 0)    {      _GLIBCXX_STD_A::partial_sort(__first, __last, __last);      return;    }  --__depth_limit;  _RandomAccessIterator __cut =    std::__unguarded_partition_pivot(__first, __last);  std::__introsort_loop(__cut, __last, __depth_limit);  __last = __cut;}    }  /// This is a helper function for the sort routine.  template<typename _RandomAccessIterator, typename _Size, typename _Compare>    void    __introsort_loop(_RandomAccessIterator __first,     _RandomAccessIterator __last,     _Size __depth_limit, _Compare __comp)    {      while (__last - __first > int(_S_threshold)){  if (__depth_limit == 0)    {      _GLIBCXX_STD_A::partial_sort(__first, __last, __last, __comp);      return;    }  --__depth_limit;  _RandomAccessIterator __cut =    std::__unguarded_partition_pivot(__first, __last, __comp);  std::__introsort_loop(__cut, __last, __depth_limit, __comp);  __last = __cut;}    }  // sort  template<typename _RandomAccessIterator, typename _Size>    void    __introselect(_RandomAccessIterator __first, _RandomAccessIterator __nth,  _RandomAccessIterator __last, _Size __depth_limit)    {      typedef typename iterator_traits<_RandomAccessIterator>::value_type_ValueType;      while (__last - __first > 3){  if (__depth_limit == 0)    {      std::__heap_select(__first, __nth + 1, __last);      // Place the nth largest element in its final position.      std::iter_swap(__first, __nth);      return;    }  --__depth_limit;  _RandomAccessIterator __cut =    std::__unguarded_partition_pivot(__first, __last);  if (__cut <= __nth)    __first = __cut;  else    __last = __cut;}      std::__insertion_sort(__first, __last);    }  template<typename _RandomAccessIterator, typename _Size, typename _Compare>    void    __introselect(_RandomAccessIterator __first, _RandomAccessIterator __nth,  _RandomAccessIterator __last, _Size __depth_limit,  _Compare __comp)    {      typedef typename iterator_traits<_RandomAccessIterator>::value_type_ValueType;      while (__last - __first > 3){  if (__depth_limit == 0)    {      std::__heap_select(__first, __nth + 1, __last, __comp);      // Place the nth largest element in its final position.      std::iter_swap(__first, __nth);      return;    }  --__depth_limit;  _RandomAccessIterator __cut =    std::__unguarded_partition_pivot(__first, __last, __comp);  if (__cut <= __nth)    __first = __cut;  else    __last = __cut;}      std::__insertion_sort(__first, __last, __comp);    }  // nth_element  // lower_bound moved to stl_algobase.h  /**   *  @brief Finds the first position in which @p __val could be inserted   *         without changing the ordering.   *  @ingroup binary_search_algorithms   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @param  __val     The search term.   *  @param  __comp    A functor to use for comparisons.   *  @return An iterator pointing to the first element <em>not less   *           than</em> @p __val, or end() if every element is less   *           than @p __val.   *  @ingroup binary_search_algorithms   *   *  The comparison function should have the same effects on ordering as   *  the function used for the initial sort.  */  template<typename _ForwardIterator, typename _Tp, typename _Compare>    _ForwardIterator    lower_bound(_ForwardIterator __first, _ForwardIterator __last,const _Tp& __val, _Compare __comp)    {      typedef typename iterator_traits<_ForwardIterator>::value_type_ValueType;      typedef typename iterator_traits<_ForwardIterator>::difference_type_DistanceType;      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _ValueType, _Tp>)      __glibcxx_requires_partitioned_lower_pred(__first, __last,__val, __comp);      _DistanceType __len = std::distance(__first, __last);      while (__len > 0){  _DistanceType __half = __len >> 1;  _ForwardIterator __middle = __first;  std::advance(__middle, __half);  if (__comp(*__middle, __val))    {      __first = __middle;      ++__first;      __len = __len - __half - 1;    }  else    __len = __half;}      return __first;    }  /**   *  @brief Finds the last position in which @p __val could be inserted   *         without changing the ordering.   *  @ingroup binary_search_algorithms   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @param  __val     The search term.   *  @return  An iterator pointing to the first element greater than @p __val,   *           or end() if no elements are greater than @p __val.   *  @ingroup binary_search_algorithms  */  template<typename _ForwardIterator, typename _Tp>    _ForwardIterator    upper_bound(_ForwardIterator __first, _ForwardIterator __last,const _Tp& __val)    {      typedef typename iterator_traits<_ForwardIterator>::value_type_ValueType;      typedef typename iterator_traits<_ForwardIterator>::difference_type_DistanceType;      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_LessThanOpConcept<_Tp, _ValueType>)      __glibcxx_requires_partitioned_upper(__first, __last, __val);      _DistanceType __len = std::distance(__first, __last);      while (__len > 0){  _DistanceType __half = __len >> 1;  _ForwardIterator __middle = __first;  std::advance(__middle, __half);  if (__val < *__middle)    __len = __half;  else    {      __first = __middle;      ++__first;      __len = __len - __half - 1;    }}      return __first;    }  /**   *  @brief Finds the last position in which @p __val could be inserted   *         without changing the ordering.   *  @ingroup binary_search_algorithms   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @param  __val     The search term.   *  @param  __comp    A functor to use for comparisons.   *  @return  An iterator pointing to the first element greater than @p __val,   *           or end() if no elements are greater than @p __val.   *  @ingroup binary_search_algorithms   *   *  The comparison function should have the same effects on ordering as   *  the function used for the initial sort.  */  template<typename _ForwardIterator, typename _Tp, typename _Compare>    _ForwardIterator    upper_bound(_ForwardIterator __first, _ForwardIterator __last,const _Tp& __val, _Compare __comp)    {      typedef typename iterator_traits<_ForwardIterator>::value_type_ValueType;      typedef typename iterator_traits<_ForwardIterator>::difference_type_DistanceType;      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _Tp, _ValueType>)      __glibcxx_requires_partitioned_upper_pred(__first, __last,__val, __comp);      _DistanceType __len = std::distance(__first, __last);      while (__len > 0){  _DistanceType __half = __len >> 1;  _ForwardIterator __middle = __first;  std::advance(__middle, __half);  if (__comp(__val, *__middle))    __len = __half;  else    {      __first = __middle;      ++__first;      __len = __len - __half - 1;    }}      return __first;    }  /**   *  @brief Finds the largest subrange in which @p __val could be inserted   *         at any place in it without changing the ordering.   *  @ingroup binary_search_algorithms   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @param  __val     The search term.   *  @return  An pair of iterators defining the subrange.   *  @ingroup binary_search_algorithms   *   *  This is equivalent to   *  @code   *    std::make_pair(lower_bound(__first, __last, __val),   *                   upper_bound(__first, __last, __val))   *  @endcode   *  but does not actually call those functions.  */  template<typename _ForwardIterator, typename _Tp>    pair<_ForwardIterator, _ForwardIterator>    equal_range(_ForwardIterator __first, _ForwardIterator __last,const _Tp& __val)    {      typedef typename iterator_traits<_ForwardIterator>::value_type_ValueType;      typedef typename iterator_traits<_ForwardIterator>::difference_type_DistanceType;      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_LessThanOpConcept<_ValueType, _Tp>)      __glibcxx_function_requires(_LessThanOpConcept<_Tp, _ValueType>)      __glibcxx_requires_partitioned_lower(__first, __last, __val);      __glibcxx_requires_partitioned_upper(__first, __last, __val);            _DistanceType __len = std::distance(__first, __last);       while (__len > 0){  _DistanceType __half = __len >> 1;  _ForwardIterator __middle = __first;  std::advance(__middle, __half);  if (*__middle < __val)    {      __first = __middle;      ++__first;      __len = __len - __half - 1;    }  else if (__val < *__middle)    __len = __half;  else    {      _ForwardIterator __left = std::lower_bound(__first, __middle, __val);      std::advance(__first, __len);      _ForwardIterator __right = std::upper_bound(++__middle, __first,  __val);      return pair<_ForwardIterator, _ForwardIterator>(__left, __right);    }}      return pair<_ForwardIterator, _ForwardIterator>(__first, __first);    }  /**   *  @brief Finds the largest subrange in which @p __val could be inserted   *         at any place in it without changing the ordering.   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @param  __val     The search term.   *  @param  __comp    A functor to use for comparisons.   *  @return  An pair of iterators defining the subrange.   *  @ingroup binary_search_algorithms   *   *  This is equivalent to   *  @code   *    std::make_pair(lower_bound(__first, __last, __val, __comp),   *                   upper_bound(__first, __last, __val, __comp))   *  @endcode   *  but does not actually call those functions.  */  template<typename _ForwardIterator, typename _Tp, typename _Compare>    pair<_ForwardIterator, _ForwardIterator>    equal_range(_ForwardIterator __first, _ForwardIterator __last,const _Tp& __val, _Compare __comp)    {      typedef typename iterator_traits<_ForwardIterator>::value_type_ValueType;      typedef typename iterator_traits<_ForwardIterator>::difference_type_DistanceType;      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _ValueType, _Tp>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _Tp, _ValueType>)      __glibcxx_requires_partitioned_lower_pred(__first, __last,__val, __comp);      __glibcxx_requires_partitioned_upper_pred(__first, __last,__val, __comp);      _DistanceType __len = std::distance(__first, __last);      while (__len > 0){  _DistanceType __half = __len >> 1;  _ForwardIterator __middle = __first;  std::advance(__middle, __half);  if (__comp(*__middle, __val))    {      __first = __middle;      ++__first;      __len = __len - __half - 1;    }  else if (__comp(__val, *__middle))    __len = __half;  else    {      _ForwardIterator __left = std::lower_bound(__first, __middle, __val, __comp);      std::advance(__first, __len);      _ForwardIterator __right = std::upper_bound(++__middle, __first,  __val, __comp);      return pair<_ForwardIterator, _ForwardIterator>(__left, __right);    }}      return pair<_ForwardIterator, _ForwardIterator>(__first, __first);    }  /**   *  @brief Determines whether an element exists in a range.   *  @ingroup binary_search_algorithms   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @param  __val     The search term.   *  @return True if @p __val (or its equivalent) is in [@p   *  __first,@p __last ].   *   *  Note that this does not actually return an iterator to @p __val.  For   *  that, use std::find or a container's specialized find member functions.  */  template<typename _ForwardIterator, typename _Tp>    bool    binary_search(_ForwardIterator __first, _ForwardIterator __last,                  const _Tp& __val)    {      typedef typename iterator_traits<_ForwardIterator>::value_type_ValueType;      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_LessThanOpConcept<_Tp, _ValueType>)      __glibcxx_requires_partitioned_lower(__first, __last, __val);      __glibcxx_requires_partitioned_upper(__first, __last, __val);      _ForwardIterator __i = std::lower_bound(__first, __last, __val);      return __i != __last && !(__val < *__i);    }  /**   *  @brief Determines whether an element exists in a range.   *  @ingroup binary_search_algorithms   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @param  __val     The search term.   *  @param  __comp    A functor to use for comparisons.   *  @return  True if @p __val (or its equivalent) is in @p [__first,__last].   *   *  Note that this does not actually return an iterator to @p __val.  For   *  that, use std::find or a container's specialized find member functions.   *   *  The comparison function should have the same effects on ordering as   *  the function used for the initial sort.  */  template<typename _ForwardIterator, typename _Tp, typename _Compare>    bool    binary_search(_ForwardIterator __first, _ForwardIterator __last,                  const _Tp& __val, _Compare __comp)    {      typedef typename iterator_traits<_ForwardIterator>::value_type_ValueType;      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _Tp, _ValueType>)      __glibcxx_requires_partitioned_lower_pred(__first, __last,__val, __comp);      __glibcxx_requires_partitioned_upper_pred(__first, __last,__val, __comp);      _ForwardIterator __i = std::lower_bound(__first, __last, __val, __comp);      return __i != __last && !bool(__comp(__val, *__i));    }  // merge  /// This is a helper function for the __merge_adaptive routines.  template<typename _InputIterator1, typename _InputIterator2,   typename _OutputIterator>    void    __move_merge_adaptive(_InputIterator1 __first1, _InputIterator1 __last1,  _InputIterator2 __first2, _InputIterator2 __last2,  _OutputIterator __result)    {      while (__first1 != __last1 && __first2 != __last2){  if (*__first2 < *__first1)    {      *__result = _GLIBCXX_MOVE(*__first2);      ++__first2;    }  else    {      *__result = _GLIBCXX_MOVE(*__first1);      ++__first1;    }  ++__result;}      if (__first1 != __last1)_GLIBCXX_MOVE3(__first1, __last1, __result);    }  /// This is a helper function for the __merge_adaptive routines.  template<typename _InputIterator1, typename _InputIterator2,   typename _OutputIterator, typename _Compare>    void    __move_merge_adaptive(_InputIterator1 __first1, _InputIterator1 __last1,  _InputIterator2 __first2, _InputIterator2 __last2,  _OutputIterator __result, _Compare __comp)    {      while (__first1 != __last1 && __first2 != __last2){  if (__comp(*__first2, *__first1))    {      *__result = _GLIBCXX_MOVE(*__first2);      ++__first2;    }  else    {      *__result = _GLIBCXX_MOVE(*__first1);      ++__first1;    }  ++__result;}      if (__first1 != __last1)_GLIBCXX_MOVE3(__first1, __last1, __result);    }  /// This is a helper function for the __merge_adaptive routines.  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,   typename _BidirectionalIterator3>    void    __move_merge_adaptive_backward(_BidirectionalIterator1 __first1,   _BidirectionalIterator1 __last1,   _BidirectionalIterator2 __first2,   _BidirectionalIterator2 __last2,   _BidirectionalIterator3 __result)    {      if (__first1 == __last1){  _GLIBCXX_MOVE_BACKWARD3(__first2, __last2, __result);  return;}      else if (__first2 == __last2)return;      --__last1;      --__last2;      while (true){  if (*__last2 < *__last1)    {      *--__result = _GLIBCXX_MOVE(*__last1);      if (__first1 == __last1){  _GLIBCXX_MOVE_BACKWARD3(__first2, ++__last2, __result);  return;}      --__last1;    }  else    {      *--__result = _GLIBCXX_MOVE(*__last2);      if (__first2 == __last2)return;      --__last2;    }}    }  /// This is a helper function for the __merge_adaptive routines.  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,   typename _BidirectionalIterator3, typename _Compare>    void    __move_merge_adaptive_backward(_BidirectionalIterator1 __first1,   _BidirectionalIterator1 __last1,   _BidirectionalIterator2 __first2,   _BidirectionalIterator2 __last2,   _BidirectionalIterator3 __result,   _Compare __comp)    {      if (__first1 == __last1){  _GLIBCXX_MOVE_BACKWARD3(__first2, __last2, __result);  return;}      else if (__first2 == __last2)return;      --__last1;      --__last2;      while (true){  if (__comp(*__last2, *__last1))    {      *--__result = _GLIBCXX_MOVE(*__last1);      if (__first1 == __last1){  _GLIBCXX_MOVE_BACKWARD3(__first2, ++__last2, __result);  return;}      --__last1;    }  else    {      *--__result = _GLIBCXX_MOVE(*__last2);      if (__first2 == __last2)return;      --__last2;    }}    }  /// This is a helper function for the merge routines.  template<typename _BidirectionalIterator1, typename _BidirectionalIterator2,   typename _Distance>    _BidirectionalIterator1    __rotate_adaptive(_BidirectionalIterator1 __first,      _BidirectionalIterator1 __middle,      _BidirectionalIterator1 __last,      _Distance __len1, _Distance __len2,      _BidirectionalIterator2 __buffer,      _Distance __buffer_size)    {      _BidirectionalIterator2 __buffer_end;      if (__len1 > __len2 && __len2 <= __buffer_size){  if (__len2)    {      __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer);      _GLIBCXX_MOVE_BACKWARD3(__first, __middle, __last);      return _GLIBCXX_MOVE3(__buffer, __buffer_end, __first);    }  else    return __first;}      else if (__len1 <= __buffer_size){  if (__len1)    {      __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer);      _GLIBCXX_MOVE3(__middle, __last, __first);      return _GLIBCXX_MOVE_BACKWARD3(__buffer, __buffer_end, __last);    }  else    return __last;}      else{  std::rotate(__first, __middle, __last);  std::advance(__first, std::distance(__middle, __last));  return __first;}    }  /// This is a helper function for the merge routines.  template<typename _BidirectionalIterator, typename _Distance,   typename _Pointer>    void    __merge_adaptive(_BidirectionalIterator __first,                     _BidirectionalIterator __middle,     _BidirectionalIterator __last,     _Distance __len1, _Distance __len2,     _Pointer __buffer, _Distance __buffer_size)    {      if (__len1 <= __len2 && __len1 <= __buffer_size){  _Pointer __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer);  std::__move_merge_adaptive(__buffer, __buffer_end, __middle, __last,     __first);}      else if (__len2 <= __buffer_size){  _Pointer __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer);  std::__move_merge_adaptive_backward(__first, __middle, __buffer,      __buffer_end, __last);}      else{  _BidirectionalIterator __first_cut = __first;  _BidirectionalIterator __second_cut = __middle;  _Distance __len11 = 0;  _Distance __len22 = 0;  if (__len1 > __len2)    {      __len11 = __len1 / 2;      std::advance(__first_cut, __len11);      __second_cut = std::lower_bound(__middle, __last,      *__first_cut);      __len22 = std::distance(__middle, __second_cut);    }  else    {      __len22 = __len2 / 2;      std::advance(__second_cut, __len22);      __first_cut = std::upper_bound(__first, __middle,     *__second_cut);      __len11 = std::distance(__first, __first_cut);    }  _BidirectionalIterator __new_middle =    std::__rotate_adaptive(__first_cut, __middle, __second_cut,   __len1 - __len11, __len22, __buffer,   __buffer_size);  std::__merge_adaptive(__first, __first_cut, __new_middle, __len11,__len22, __buffer, __buffer_size);  std::__merge_adaptive(__new_middle, __second_cut, __last,__len1 - __len11,__len2 - __len22, __buffer, __buffer_size);}    }  /// This is a helper function for the merge routines.  template<typename _BidirectionalIterator, typename _Distance,    typename _Pointer, typename _Compare>    void    __merge_adaptive(_BidirectionalIterator __first,                     _BidirectionalIterator __middle,     _BidirectionalIterator __last,     _Distance __len1, _Distance __len2,     _Pointer __buffer, _Distance __buffer_size,     _Compare __comp)    {      if (__len1 <= __len2 && __len1 <= __buffer_size){  _Pointer __buffer_end = _GLIBCXX_MOVE3(__first, __middle, __buffer);  std::__move_merge_adaptive(__buffer, __buffer_end, __middle, __last,     __first, __comp);}      else if (__len2 <= __buffer_size){  _Pointer __buffer_end = _GLIBCXX_MOVE3(__middle, __last, __buffer);  std::__move_merge_adaptive_backward(__first, __middle, __buffer,      __buffer_end, __last, __comp);}      else{  _BidirectionalIterator __first_cut = __first;  _BidirectionalIterator __second_cut = __middle;  _Distance __len11 = 0;  _Distance __len22 = 0;  if (__len1 > __len2)    {      __len11 = __len1 / 2;      std::advance(__first_cut, __len11);      __second_cut = std::lower_bound(__middle, __last, *__first_cut,      __comp);      __len22 = std::distance(__middle, __second_cut);    }  else    {      __len22 = __len2 / 2;      std::advance(__second_cut, __len22);      __first_cut = std::upper_bound(__first, __middle, *__second_cut,     __comp);      __len11 = std::distance(__first, __first_cut);    }  _BidirectionalIterator __new_middle =    std::__rotate_adaptive(__first_cut, __middle, __second_cut,   __len1 - __len11, __len22, __buffer,   __buffer_size);  std::__merge_adaptive(__first, __first_cut, __new_middle, __len11,__len22, __buffer, __buffer_size, __comp);  std::__merge_adaptive(__new_middle, __second_cut, __last,__len1 - __len11,__len2 - __len22, __buffer,__buffer_size, __comp);}    }  /// This is a helper function for the merge routines.  template<typename _BidirectionalIterator, typename _Distance>    void    __merge_without_buffer(_BidirectionalIterator __first,   _BidirectionalIterator __middle,   _BidirectionalIterator __last,   _Distance __len1, _Distance __len2)    {      if (__len1 == 0 || __len2 == 0)return;      if (__len1 + __len2 == 2){  if (*__middle < *__first)    std::iter_swap(__first, __middle);  return;}      _BidirectionalIterator __first_cut = __first;      _BidirectionalIterator __second_cut = __middle;      _Distance __len11 = 0;      _Distance __len22 = 0;      if (__len1 > __len2){  __len11 = __len1 / 2;  std::advance(__first_cut, __len11);  __second_cut = std::lower_bound(__middle, __last, *__first_cut);  __len22 = std::distance(__middle, __second_cut);}      else{  __len22 = __len2 / 2;  std::advance(__second_cut, __len22);  __first_cut = std::upper_bound(__first, __middle, *__second_cut);  __len11 = std::distance(__first, __first_cut);}      std::rotate(__first_cut, __middle, __second_cut);      _BidirectionalIterator __new_middle = __first_cut;      std::advance(__new_middle, std::distance(__middle, __second_cut));      std::__merge_without_buffer(__first, __first_cut, __new_middle,  __len11, __len22);      std::__merge_without_buffer(__new_middle, __second_cut, __last,  __len1 - __len11, __len2 - __len22);    }  /// This is a helper function for the merge routines.  template<typename _BidirectionalIterator, typename _Distance,   typename _Compare>    void    __merge_without_buffer(_BidirectionalIterator __first,                           _BidirectionalIterator __middle,   _BidirectionalIterator __last,   _Distance __len1, _Distance __len2,   _Compare __comp)    {      if (__len1 == 0 || __len2 == 0)return;      if (__len1 + __len2 == 2){  if (__comp(*__middle, *__first))    std::iter_swap(__first, __middle);  return;}      _BidirectionalIterator __first_cut = __first;      _BidirectionalIterator __second_cut = __middle;      _Distance __len11 = 0;      _Distance __len22 = 0;      if (__len1 > __len2){  __len11 = __len1 / 2;  std::advance(__first_cut, __len11);  __second_cut = std::lower_bound(__middle, __last, *__first_cut,  __comp);  __len22 = std::distance(__middle, __second_cut);}      else{  __len22 = __len2 / 2;  std::advance(__second_cut, __len22);  __first_cut = std::upper_bound(__first, __middle, *__second_cut, __comp);  __len11 = std::distance(__first, __first_cut);}      std::rotate(__first_cut, __middle, __second_cut);      _BidirectionalIterator __new_middle = __first_cut;      std::advance(__new_middle, std::distance(__middle, __second_cut));      std::__merge_without_buffer(__first, __first_cut, __new_middle,  __len11, __len22, __comp);      std::__merge_without_buffer(__new_middle, __second_cut, __last,  __len1 - __len11, __len2 - __len22, __comp);    }  /**   *  @brief Merges two sorted ranges in place.   *  @ingroup sorting_algorithms   *  @param  __first   An iterator.   *  @param  __middle  Another iterator.   *  @param  __last    Another iterator.   *  @return  Nothing.   *   *  Merges two sorted and consecutive ranges, [__first,__middle) and   *  [__middle,__last), and puts the result in [__first,__last).  The   *  output will be sorted.  The sort is @e stable, that is, for   *  equivalent elements in the two ranges, elements from the first   *  range will always come before elements from the second.   *   *  If enough additional memory is available, this takes (__last-__first)-1   *  comparisons.  Otherwise an NlogN algorithm is used, where N is   *  distance(__first,__last).  */  template<typename _BidirectionalIterator>    void    inplace_merge(_BidirectionalIterator __first,  _BidirectionalIterator __middle,  _BidirectionalIterator __last)    {      typedef typename iterator_traits<_BidirectionalIterator>::value_type          _ValueType;      typedef typename iterator_traits<_BidirectionalIterator>::difference_type          _DistanceType;      // concept requirements      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<    _BidirectionalIterator>)      __glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)      __glibcxx_requires_sorted(__first, __middle);      __glibcxx_requires_sorted(__middle, __last);      if (__first == __middle || __middle == __last)return;      _DistanceType __len1 = std::distance(__first, __middle);      _DistanceType __len2 = std::distance(__middle, __last);      _Temporary_buffer<_BidirectionalIterator, _ValueType> __buf(__first,  __last);      if (__buf.begin() == 0)std::__merge_without_buffer(__first, __middle, __last, __len1, __len2);      elsestd::__merge_adaptive(__first, __middle, __last, __len1, __len2,      __buf.begin(), _DistanceType(__buf.size()));    }  /**   *  @brief Merges two sorted ranges in place.   *  @ingroup sorting_algorithms   *  @param  __first   An iterator.   *  @param  __middle  Another iterator.   *  @param  __last    Another iterator.   *  @param  __comp    A functor to use for comparisons.   *  @return  Nothing.   *   *  Merges two sorted and consecutive ranges, [__first,__middle) and   *  [middle,last), and puts the result in [__first,__last).  The output will   *  be sorted.  The sort is @e stable, that is, for equivalent   *  elements in the two ranges, elements from the first range will always   *  come before elements from the second.   *   *  If enough additional memory is available, this takes (__last-__first)-1   *  comparisons.  Otherwise an NlogN algorithm is used, where N is   *  distance(__first,__last).   *   *  The comparison function should have the same effects on ordering as   *  the function used for the initial sort.  */  template<typename _BidirectionalIterator, typename _Compare>    void    inplace_merge(_BidirectionalIterator __first,  _BidirectionalIterator __middle,  _BidirectionalIterator __last,  _Compare __comp)    {      typedef typename iterator_traits<_BidirectionalIterator>::value_type          _ValueType;      typedef typename iterator_traits<_BidirectionalIterator>::difference_type          _DistanceType;      // concept requirements      __glibcxx_function_requires(_Mutable_BidirectionalIteratorConcept<    _BidirectionalIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,    _ValueType, _ValueType>)      __glibcxx_requires_sorted_pred(__first, __middle, __comp);      __glibcxx_requires_sorted_pred(__middle, __last, __comp);      if (__first == __middle || __middle == __last)return;      const _DistanceType __len1 = std::distance(__first, __middle);      const _DistanceType __len2 = std::distance(__middle, __last);      _Temporary_buffer<_BidirectionalIterator, _ValueType> __buf(__first,  __last);      if (__buf.begin() == 0)std::__merge_without_buffer(__first, __middle, __last, __len1,    __len2, __comp);      elsestd::__merge_adaptive(__first, __middle, __last, __len1, __len2,      __buf.begin(), _DistanceType(__buf.size()),      __comp);    }  /// This is a helper function for the __merge_sort_loop routines.  template<typename _InputIterator1, typename _InputIterator2,   typename _OutputIterator>    _OutputIterator    __move_merge(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result)    {      while (__first1 != __last1 && __first2 != __last2){  if (*__first2 < *__first1)    {      *__result = _GLIBCXX_MOVE(*__first2);      ++__first2;    }  else    {      *__result = _GLIBCXX_MOVE(*__first1);      ++__first1;    }  ++__result;}      return _GLIBCXX_MOVE3(__first2, __last2,    _GLIBCXX_MOVE3(__first1, __last1,   __result));    }  /// This is a helper function for the __merge_sort_loop routines.  template<typename _InputIterator1, typename _InputIterator2,   typename _OutputIterator, typename _Compare>    _OutputIterator    __move_merge(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _InputIterator2 __last2, _OutputIterator __result, _Compare __comp)    {      while (__first1 != __last1 && __first2 != __last2){  if (__comp(*__first2, *__first1))    {      *__result = _GLIBCXX_MOVE(*__first2);      ++__first2;    }  else    {      *__result = _GLIBCXX_MOVE(*__first1);      ++__first1;    }  ++__result;}      return _GLIBCXX_MOVE3(__first2, __last2,    _GLIBCXX_MOVE3(__first1, __last1,   __result));    }  template<typename _RandomAccessIterator1, typename _RandomAccessIterator2,   typename _Distance>    void    __merge_sort_loop(_RandomAccessIterator1 __first,      _RandomAccessIterator1 __last,      _RandomAccessIterator2 __result,      _Distance __step_size)    {      const _Distance __two_step = 2 * __step_size;      while (__last - __first >= __two_step){  __result = std::__move_merge(__first, __first + __step_size,       __first + __step_size,       __first + __two_step, __result);  __first += __two_step;}      __step_size = std::min(_Distance(__last - __first), __step_size);      std::__move_merge(__first, __first + __step_size,__first + __step_size, __last, __result);    }  template<typename _RandomAccessIterator1, typename _RandomAccessIterator2,   typename _Distance, typename _Compare>    void    __merge_sort_loop(_RandomAccessIterator1 __first,      _RandomAccessIterator1 __last,      _RandomAccessIterator2 __result, _Distance __step_size,      _Compare __comp)    {      const _Distance __two_step = 2 * __step_size;      while (__last - __first >= __two_step){  __result = std::__move_merge(__first, __first + __step_size,       __first + __step_size,       __first + __two_step,       __result, __comp);  __first += __two_step;}      __step_size = std::min(_Distance(__last - __first), __step_size);      std::__move_merge(__first,__first + __step_size,__first + __step_size, __last, __result, __comp);    }  template<typename _RandomAccessIterator, typename _Distance>    void    __chunk_insertion_sort(_RandomAccessIterator __first,   _RandomAccessIterator __last,   _Distance __chunk_size)    {      while (__last - __first >= __chunk_size){  std::__insertion_sort(__first, __first + __chunk_size);  __first += __chunk_size;}      std::__insertion_sort(__first, __last);    }  template<typename _RandomAccessIterator, typename _Distance,   typename _Compare>    void    __chunk_insertion_sort(_RandomAccessIterator __first,   _RandomAccessIterator __last,   _Distance __chunk_size, _Compare __comp)    {      while (__last - __first >= __chunk_size){  std::__insertion_sort(__first, __first + __chunk_size, __comp);  __first += __chunk_size;}      std::__insertion_sort(__first, __last, __comp);    }  enum { _S_chunk_size = 7 };  template<typename _RandomAccessIterator, typename _Pointer>    void    __merge_sort_with_buffer(_RandomAccessIterator __first,     _RandomAccessIterator __last,                             _Pointer __buffer)    {      typedef typename iterator_traits<_RandomAccessIterator>::difference_type_Distance;      const _Distance __len = __last - __first;      const _Pointer __buffer_last = __buffer + __len;      _Distance __step_size = _S_chunk_size;      std::__chunk_insertion_sort(__first, __last, __step_size);      while (__step_size < __len){  std::__merge_sort_loop(__first, __last, __buffer, __step_size);  __step_size *= 2;  std::__merge_sort_loop(__buffer, __buffer_last, __first, __step_size);  __step_size *= 2;}    }  template<typename _RandomAccessIterator, typename _Pointer, typename _Compare>    void    __merge_sort_with_buffer(_RandomAccessIterator __first,     _RandomAccessIterator __last,                             _Pointer __buffer, _Compare __comp)    {      typedef typename iterator_traits<_RandomAccessIterator>::difference_type_Distance;      const _Distance __len = __last - __first;      const _Pointer __buffer_last = __buffer + __len;      _Distance __step_size = _S_chunk_size;      std::__chunk_insertion_sort(__first, __last, __step_size, __comp);      while (__step_size < __len){  std::__merge_sort_loop(__first, __last, __buffer, __step_size, __comp);  __step_size *= 2;  std::__merge_sort_loop(__buffer, __buffer_last, __first, __step_size, __comp);  __step_size *= 2;}    }  template<typename _RandomAccessIterator, typename _Pointer,   typename _Distance>    void    __stable_sort_adaptive(_RandomAccessIterator __first,   _RandomAccessIterator __last,                           _Pointer __buffer, _Distance __buffer_size)    {      const _Distance __len = (__last - __first + 1) / 2;      const _RandomAccessIterator __middle = __first + __len;      if (__len > __buffer_size){  std::__stable_sort_adaptive(__first, __middle,      __buffer, __buffer_size);  std::__stable_sort_adaptive(__middle, __last,      __buffer, __buffer_size);}      else{  std::__merge_sort_with_buffer(__first, __middle, __buffer);  std::__merge_sort_with_buffer(__middle, __last, __buffer);}      std::__merge_adaptive(__first, __middle, __last,    _Distance(__middle - __first),    _Distance(__last - __middle),    __buffer, __buffer_size);    }  template<typename _RandomAccessIterator, typename _Pointer,   typename _Distance, typename _Compare>    void    __stable_sort_adaptive(_RandomAccessIterator __first,   _RandomAccessIterator __last,                           _Pointer __buffer, _Distance __buffer_size,                           _Compare __comp)    {      const _Distance __len = (__last - __first + 1) / 2;      const _RandomAccessIterator __middle = __first + __len;      if (__len > __buffer_size){  std::__stable_sort_adaptive(__first, __middle, __buffer,      __buffer_size, __comp);  std::__stable_sort_adaptive(__middle, __last, __buffer,      __buffer_size, __comp);}      else{  std::__merge_sort_with_buffer(__first, __middle, __buffer, __comp);  std::__merge_sort_with_buffer(__middle, __last, __buffer, __comp);}      std::__merge_adaptive(__first, __middle, __last,    _Distance(__middle - __first),    _Distance(__last - __middle),    __buffer, __buffer_size,    __comp);    }  /// This is a helper function for the stable sorting routines.  template<typename _RandomAccessIterator>    void    __inplace_stable_sort(_RandomAccessIterator __first,  _RandomAccessIterator __last)    {      if (__last - __first < 15){  std::__insertion_sort(__first, __last);  return;}      _RandomAccessIterator __middle = __first + (__last - __first) / 2;      std::__inplace_stable_sort(__first, __middle);      std::__inplace_stable_sort(__middle, __last);      std::__merge_without_buffer(__first, __middle, __last,  __middle - __first,  __last - __middle);    }  /// This is a helper function for the stable sorting routines.  template<typename _RandomAccessIterator, typename _Compare>    void    __inplace_stable_sort(_RandomAccessIterator __first,  _RandomAccessIterator __last, _Compare __comp)    {      if (__last - __first < 15){  std::__insertion_sort(__first, __last, __comp);  return;}      _RandomAccessIterator __middle = __first + (__last - __first) / 2;      std::__inplace_stable_sort(__first, __middle, __comp);      std::__inplace_stable_sort(__middle, __last, __comp);      std::__merge_without_buffer(__first, __middle, __last,  __middle - __first,  __last - __middle,  __comp);    }  // stable_sort  // Set algorithms: includes, set_union, set_intersection, set_difference,  // set_symmetric_difference.  All of these algorithms have the precondition  // that their input ranges are sorted and the postcondition that their output  // ranges are sorted.  /**   *  @brief Determines whether all elements of a sequence exists in a range.   *  @param  __first1  Start of search range.   *  @param  __last1   End of search range.   *  @param  __first2  Start of sequence   *  @param  __last2   End of sequence.   *  @return  True if each element in [__first2,__last2) is contained in order   *  within [__first1,__last1).  False otherwise.   *  @ingroup set_algorithms   *   *  This operation expects both [__first1,__last1) and   *  [__first2,__last2) to be sorted.  Searches for the presence of   *  each element in [__first2,__last2) within [__first1,__last1).   *  The iterators over each range only move forward, so this is a   *  linear algorithm.  If an element in [__first2,__last2) is not   *  found before the search iterator reaches @p __last2, false is   *  returned.  */  template<typename _InputIterator1, typename _InputIterator2>    bool    includes(_InputIterator1 __first1, _InputIterator1 __last1,     _InputIterator2 __first2, _InputIterator2 __last2)    {      typedef typename iterator_traits<_InputIterator1>::value_type_ValueType1;      typedef typename iterator_traits<_InputIterator2>::value_type_ValueType2;      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)      __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)      __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)      __glibcxx_requires_sorted_set(__first1, __last1, __first2);      __glibcxx_requires_sorted_set(__first2, __last2, __first1);      while (__first1 != __last1 && __first2 != __last2)if (*__first2 < *__first1)  return false;else if(*__first1 < *__first2)  ++__first1;else  ++__first1, ++__first2;      return __first2 == __last2;    }  /**   *  @brief Determines whether all elements of a sequence exists in a range   *  using comparison.   *  @ingroup set_algorithms   *  @param  __first1  Start of search range.   *  @param  __last1   End of search range.   *  @param  __first2  Start of sequence   *  @param  __last2   End of sequence.   *  @param  __comp    Comparison function to use.   *  @return True if each element in [__first2,__last2) is contained   *  in order within [__first1,__last1) according to comp.  False   *  otherwise.  @ingroup set_algorithms   *   *  This operation expects both [__first1,__last1) and   *  [__first2,__last2) to be sorted.  Searches for the presence of   *  each element in [__first2,__last2) within [__first1,__last1),   *  using comp to decide.  The iterators over each range only move   *  forward, so this is a linear algorithm.  If an element in   *  [__first2,__last2) is not found before the search iterator   *  reaches @p __last2, false is returned.  */  template<typename _InputIterator1, typename _InputIterator2,   typename _Compare>    bool    includes(_InputIterator1 __first1, _InputIterator1 __last1,     _InputIterator2 __first2, _InputIterator2 __last2,     _Compare __comp)    {      typedef typename iterator_traits<_InputIterator1>::value_type_ValueType1;      typedef typename iterator_traits<_InputIterator2>::value_type_ValueType2;      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _ValueType1, _ValueType2>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _ValueType2, _ValueType1>)      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);      while (__first1 != __last1 && __first2 != __last2)if (__comp(*__first2, *__first1))  return false;else if(__comp(*__first1, *__first2))  ++__first1;else  ++__first1, ++__first2;      return __first2 == __last2;    }  // nth_element  // merge  // set_difference  // set_intersection  // set_union  // stable_sort  // set_symmetric_difference  // min_element  // max_element  /**   *  @brief  Permute range into the next @e dictionary ordering.   *  @ingroup sorting_algorithms   *  @param  __first  Start of range.   *  @param  __last   End of range.   *  @return  False if wrapped to first permutation, true otherwise.   *   *  Treats all permutations of the range as a set of @e dictionary sorted   *  sequences.  Permutes the current sequence into the next one of this set.   *  Returns true if there are more sequences to generate.  If the sequence   *  is the largest of the set, the smallest is generated and false returned.  */  template<typename _BidirectionalIterator>    bool    next_permutation(_BidirectionalIterator __first,     _BidirectionalIterator __last)    {      // concept requirements      __glibcxx_function_requires(_BidirectionalIteratorConcept<  _BidirectionalIterator>)      __glibcxx_function_requires(_LessThanComparableConcept<    typename iterator_traits<_BidirectionalIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      if (__first == __last)return false;      _BidirectionalIterator __i = __first;      ++__i;      if (__i == __last)return false;      __i = __last;      --__i;      for(;;){  _BidirectionalIterator __ii = __i;  --__i;  if (*__i < *__ii)    {      _BidirectionalIterator __j = __last;      while (!(*__i < *--__j)){}      std::iter_swap(__i, __j);      std::reverse(__ii, __last);      return true;    }  if (__i == __first)    {      std::reverse(__first, __last);      return false;    }}    }  /**   *  @brief  Permute range into the next @e dictionary ordering using   *          comparison functor.   *  @ingroup sorting_algorithms   *  @param  __first  Start of range.   *  @param  __last   End of range.   *  @param  __comp   A comparison functor.   *  @return  False if wrapped to first permutation, true otherwise.   *   *  Treats all permutations of the range [__first,__last) as a set of   *  @e dictionary sorted sequences ordered by @p __comp.  Permutes the current   *  sequence into the next one of this set.  Returns true if there are more   *  sequences to generate.  If the sequence is the largest of the set, the   *  smallest is generated and false returned.  */  template<typename _BidirectionalIterator, typename _Compare>    bool    next_permutation(_BidirectionalIterator __first,     _BidirectionalIterator __last, _Compare __comp)    {      // concept requirements      __glibcxx_function_requires(_BidirectionalIteratorConcept<  _BidirectionalIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,    typename iterator_traits<_BidirectionalIterator>::value_type,    typename iterator_traits<_BidirectionalIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      if (__first == __last)return false;      _BidirectionalIterator __i = __first;      ++__i;      if (__i == __last)return false;      __i = __last;      --__i;      for(;;){  _BidirectionalIterator __ii = __i;  --__i;  if (__comp(*__i, *__ii))    {      _BidirectionalIterator __j = __last;      while (!bool(__comp(*__i, *--__j))){}      std::iter_swap(__i, __j);      std::reverse(__ii, __last);      return true;    }  if (__i == __first)    {      std::reverse(__first, __last);      return false;    }}    }  /**   *  @brief  Permute range into the previous @e dictionary ordering.   *  @ingroup sorting_algorithms   *  @param  __first  Start of range.   *  @param  __last   End of range.   *  @return  False if wrapped to last permutation, true otherwise.   *   *  Treats all permutations of the range as a set of @e dictionary sorted   *  sequences.  Permutes the current sequence into the previous one of this   *  set.  Returns true if there are more sequences to generate.  If the   *  sequence is the smallest of the set, the largest is generated and false   *  returned.  */  template<typename _BidirectionalIterator>    bool    prev_permutation(_BidirectionalIterator __first,     _BidirectionalIterator __last)    {      // concept requirements      __glibcxx_function_requires(_BidirectionalIteratorConcept<  _BidirectionalIterator>)      __glibcxx_function_requires(_LessThanComparableConcept<    typename iterator_traits<_BidirectionalIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      if (__first == __last)return false;      _BidirectionalIterator __i = __first;      ++__i;      if (__i == __last)return false;      __i = __last;      --__i;      for(;;){  _BidirectionalIterator __ii = __i;  --__i;  if (*__ii < *__i)    {      _BidirectionalIterator __j = __last;      while (!(*--__j < *__i)){}      std::iter_swap(__i, __j);      std::reverse(__ii, __last);      return true;    }  if (__i == __first)    {      std::reverse(__first, __last);      return false;    }}    }  /**   *  @brief  Permute range into the previous @e dictionary ordering using   *          comparison functor.   *  @ingroup sorting_algorithms   *  @param  __first  Start of range.   *  @param  __last   End of range.   *  @param  __comp   A comparison functor.   *  @return  False if wrapped to last permutation, true otherwise.   *   *  Treats all permutations of the range [__first,__last) as a set of   *  @e dictionary sorted sequences ordered by @p __comp.  Permutes the current   *  sequence into the previous one of this set.  Returns true if there are   *  more sequences to generate.  If the sequence is the smallest of the set,   *  the largest is generated and false returned.  */  template<typename _BidirectionalIterator, typename _Compare>    bool    prev_permutation(_BidirectionalIterator __first,     _BidirectionalIterator __last, _Compare __comp)    {      // concept requirements      __glibcxx_function_requires(_BidirectionalIteratorConcept<  _BidirectionalIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,    typename iterator_traits<_BidirectionalIterator>::value_type,    typename iterator_traits<_BidirectionalIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      if (__first == __last)return false;      _BidirectionalIterator __i = __first;      ++__i;      if (__i == __last)return false;      __i = __last;      --__i;      for(;;){  _BidirectionalIterator __ii = __i;  --__i;  if (__comp(*__ii, *__i))    {      _BidirectionalIterator __j = __last;      while (!bool(__comp(*--__j, *__i))){}      std::iter_swap(__i, __j);      std::reverse(__ii, __last);      return true;    }  if (__i == __first)    {      std::reverse(__first, __last);      return false;    }}    }  // replace  // replace_if  /**   *  @brief Copy a sequence, replacing each element of one value with another   *         value.   *  @param  __first      An input iterator.   *  @param  __last       An input iterator.   *  @param  __result     An output iterator.   *  @param  __old_value  The value to be replaced.   *  @param  __new_value  The replacement value.   *  @return   The end of the output sequence, @p result+(last-first).   *   *  Copies each element in the input range @p [__first,__last) to the   *  output range @p [__result,__result+(__last-__first)) replacing elements   *  equal to @p __old_value with @p __new_value.  */  template<typename _InputIterator, typename _OutputIterator, typename _Tp>    _OutputIterator    replace_copy(_InputIterator __first, _InputIterator __last, _OutputIterator __result, const _Tp& __old_value, const _Tp& __new_value)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,    typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_function_requires(_EqualOpConcept<    typename iterator_traits<_InputIterator>::value_type, _Tp>)      __glibcxx_requires_valid_range(__first, __last);      for (; __first != __last; ++__first, ++__result)if (*__first == __old_value)  *__result = __new_value;else  *__result = *__first;      return __result;    }  /**   *  @brief Copy a sequence, replacing each value for which a predicate   *         returns true with another value.   *  @ingroup mutating_algorithms   *  @param  __first      An input iterator.   *  @param  __last       An input iterator.   *  @param  __result     An output iterator.   *  @param  __pred       A predicate.   *  @param  __new_value  The replacement value.   *  @return   The end of the output sequence, @p __result+(__last-__first).   *   *  Copies each element in the range @p [__first,__last) to the range   *  @p [__result,__result+(__last-__first)) replacing elements for which   *  @p __pred returns true with @p __new_value.  */  template<typename _InputIterator, typename _OutputIterator,   typename _Predicate, typename _Tp>    _OutputIterator    replace_copy_if(_InputIterator __first, _InputIterator __last,    _OutputIterator __result,    _Predicate __pred, const _Tp& __new_value)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,    typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,    typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      for (; __first != __last; ++__first, ++__result)if (__pred(*__first))  *__result = __new_value;else  *__result = *__first;      return __result;    }#ifdef __GXX_EXPERIMENTAL_CXX0X__  /**   *  @brief  Determines whether the elements of a sequence are sorted.   *  @ingroup sorting_algorithms   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @return  True if the elements are sorted, false otherwise.  */  template<typename _ForwardIterator>    inline bool    is_sorted(_ForwardIterator __first, _ForwardIterator __last)    { return std::is_sorted_until(__first, __last) == __last; }  /**   *  @brief  Determines whether the elements of a sequence are sorted   *          according to a comparison functor.   *  @ingroup sorting_algorithms   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @param  __comp    A comparison functor.   *  @return  True if the elements are sorted, false otherwise.  */  template<typename _ForwardIterator, typename _Compare>    inline bool    is_sorted(_ForwardIterator __first, _ForwardIterator __last,      _Compare __comp)    { return std::is_sorted_until(__first, __last, __comp) == __last; }  /**   *  @brief  Determines the end of a sorted sequence.   *  @ingroup sorting_algorithms   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @return  An iterator pointing to the last iterator i in [__first, __last)   *           for which the range [__first, i) is sorted.  */  template<typename _ForwardIterator>    _ForwardIterator    is_sorted_until(_ForwardIterator __first, _ForwardIterator __last)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_LessThanComparableConcept<    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      if (__first == __last)return __last;      _ForwardIterator __next = __first;      for (++__next; __next != __last; __first = __next, ++__next)if (*__next < *__first)  return __next;      return __next;    }  /**   *  @brief  Determines the end of a sorted sequence using comparison functor.   *  @ingroup sorting_algorithms   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @param  __comp    A comparison functor.   *  @return  An iterator pointing to the last iterator i in [__first, __last)   *           for which the range [__first, i) is sorted.  */  template<typename _ForwardIterator, typename _Compare>    _ForwardIterator    is_sorted_until(_ForwardIterator __first, _ForwardIterator __last,    _Compare __comp)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,    typename iterator_traits<_ForwardIterator>::value_type,    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      if (__first == __last)return __last;      _ForwardIterator __next = __first;      for (++__next; __next != __last; __first = __next, ++__next)if (__comp(*__next, *__first))  return __next;      return __next;    }  /**   *  @brief  Determines min and max at once as an ordered pair.   *  @ingroup sorting_algorithms   *  @param  __a  A thing of arbitrary type.   *  @param  __b  Another thing of arbitrary type.   *  @return A pair(__b, __a) if __b is smaller than __a, pair(__a,   *  __b) otherwise.  */  template<typename _Tp>    inline pair<const _Tp&, const _Tp&>    minmax(const _Tp& __a, const _Tp& __b)    {      // concept requirements      __glibcxx_function_requires(_LessThanComparableConcept<_Tp>)      return __b < __a ? pair<const _Tp&, const _Tp&>(__b, __a)               : pair<const _Tp&, const _Tp&>(__a, __b);    }  /**   *  @brief  Determines min and max at once as an ordered pair.   *  @ingroup sorting_algorithms   *  @param  __a  A thing of arbitrary type.   *  @param  __b  Another thing of arbitrary type.   *  @param  __comp  A @link comparison_functors comparison functor @endlink.   *  @return A pair(__b, __a) if __b is smaller than __a, pair(__a,   *  __b) otherwise.  */  template<typename _Tp, typename _Compare>    inline pair<const _Tp&, const _Tp&>    minmax(const _Tp& __a, const _Tp& __b, _Compare __comp)    {      return __comp(__b, __a) ? pair<const _Tp&, const _Tp&>(__b, __a)                      : pair<const _Tp&, const _Tp&>(__a, __b);    }  /**   *  @brief  Return a pair of iterators pointing to the minimum and maximum   *          elements in a range.   *  @ingroup sorting_algorithms   *  @param  __first  Start of range.   *  @param  __last   End of range.   *  @return  make_pair(m, M), where m is the first iterator i in    *           [__first, __last) such that no other element in the range is   *           smaller, and where M is the last iterator i in [__first, __last)   *           such that no other element in the range is larger.  */  template<typename _ForwardIterator>    pair<_ForwardIterator, _ForwardIterator>    minmax_element(_ForwardIterator __first, _ForwardIterator __last)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_LessThanComparableConcept<    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      _ForwardIterator __next = __first;      if (__first == __last  || ++__next == __last)return std::make_pair(__first, __first);      _ForwardIterator __min, __max;      if (*__next < *__first){  __min = __next;  __max = __first;}      else{  __min = __first;  __max = __next;}      __first = __next;      ++__first;      while (__first != __last){  __next = __first;  if (++__next == __last)    {      if (*__first < *__min)__min = __first;      else if (!(*__first < *__max))__max = __first;      break;    }  if (*__next < *__first)    {      if (*__next < *__min)__min = __next;      if (!(*__first < *__max))__max = __first;    }  else    {      if (*__first < *__min)__min = __first;      if (!(*__next < *__max))__max = __next;    }  __first = __next;  ++__first;}      return std::make_pair(__min, __max);    }  /**   *  @brief  Return a pair of iterators pointing to the minimum and maximum   *          elements in a range.   *  @ingroup sorting_algorithms   *  @param  __first  Start of range.   *  @param  __last   End of range.   *  @param  __comp   Comparison functor.   *  @return  make_pair(m, M), where m is the first iterator i in    *           [__first, __last) such that no other element in the range is   *           smaller, and where M is the last iterator i in [__first, __last)   *           such that no other element in the range is larger.  */  template<typename _ForwardIterator, typename _Compare>    pair<_ForwardIterator, _ForwardIterator>    minmax_element(_ForwardIterator __first, _ForwardIterator __last,   _Compare __comp)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,    typename iterator_traits<_ForwardIterator>::value_type,    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      _ForwardIterator __next = __first;      if (__first == __last  || ++__next == __last)return std::make_pair(__first, __first);      _ForwardIterator __min, __max;      if (__comp(*__next, *__first)){  __min = __next;  __max = __first;}      else{  __min = __first;  __max = __next;}      __first = __next;      ++__first;      while (__first != __last){  __next = __first;  if (++__next == __last)    {      if (__comp(*__first, *__min))__min = __first;      else if (!__comp(*__first, *__max))__max = __first;      break;    }  if (__comp(*__next, *__first))    {      if (__comp(*__next, *__min))__min = __next;      if (!__comp(*__first, *__max))__max = __first;    }  else    {      if (__comp(*__first, *__min))__min = __first;      if (!__comp(*__next, *__max))__max = __next;    }  __first = __next;  ++__first;}      return std::make_pair(__min, __max);    }  // N2722 + DR 915.  template<typename _Tp>    inline _Tp    min(initializer_list<_Tp> __l)    { return *std::min_element(__l.begin(), __l.end()); }  template<typename _Tp, typename _Compare>    inline _Tp    min(initializer_list<_Tp> __l, _Compare __comp)    { return *std::min_element(__l.begin(), __l.end(), __comp); }  template<typename _Tp>    inline _Tp    max(initializer_list<_Tp> __l)    { return *std::max_element(__l.begin(), __l.end()); }  template<typename _Tp, typename _Compare>    inline _Tp    max(initializer_list<_Tp> __l, _Compare __comp)    { return *std::max_element(__l.begin(), __l.end(), __comp); }  template<typename _Tp>    inline pair<_Tp, _Tp>    minmax(initializer_list<_Tp> __l)    {      pair<const _Tp*, const _Tp*> __p =std::minmax_element(__l.begin(), __l.end());      return std::make_pair(*__p.first, *__p.second);    }  template<typename _Tp, typename _Compare>    inline pair<_Tp, _Tp>    minmax(initializer_list<_Tp> __l, _Compare __comp)    {      pair<const _Tp*, const _Tp*> __p =std::minmax_element(__l.begin(), __l.end(), __comp);      return std::make_pair(*__p.first, *__p.second);    }  /**   *  @brief  Checks whether a permutaion of the second sequence is equal   *          to the first sequence.   *  @ingroup non_mutating_algorithms   *  @param  __first1  Start of first range.   *  @param  __last1   End of first range.   *  @param  __first2  Start of second range.   *  @return true if there exists a permutation of the elements in the range   *          [__first2, __first2 + (__last1 - __first1)), beginning with    *          ForwardIterator2 begin, such that equal(__first1, __last1, begin)   *          returns true; otherwise, returns false.  */  template<typename _ForwardIterator1, typename _ForwardIterator2>    bool    is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,   _ForwardIterator2 __first2)    {      // Efficiently compare identical prefixes:  O(N) if sequences      // have the same elements in the same order.      for (; __first1 != __last1; ++__first1, ++__first2)if (!(*__first1 == *__first2))  break;      if (__first1 == __last1)return true;      // Establish __last2 assuming equal ranges by iterating over the      // rest of the list.      _ForwardIterator2 __last2 = __first2;      std::advance(__last2, std::distance(__first1, __last1));      for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan){  if (__scan != _GLIBCXX_STD_A::find(__first1, __scan, *__scan))    continue; // We've seen this one before.  auto __matches = std::count(__first2, __last2, *__scan);  if (0 == __matches      || std::count(__scan, __last1, *__scan) != __matches)    return false;}      return true;    }  /**   *  @brief  Checks whether a permutation of the second sequence is equal   *          to the first sequence.   *  @ingroup non_mutating_algorithms   *  @param  __first1  Start of first range.   *  @param  __last1   End of first range.   *  @param  __first2  Start of second range.   *  @param  __pred    A binary predicate.   *  @return true if there exists a permutation of the elements in   *          the range [__first2, __first2 + (__last1 - __first1)),   *          beginning with ForwardIterator2 begin, such that   *          equal(__first1, __last1, __begin, __pred) returns true;   *          otherwise, returns false.  */  template<typename _ForwardIterator1, typename _ForwardIterator2,   typename _BinaryPredicate>    bool    is_permutation(_ForwardIterator1 __first1, _ForwardIterator1 __last1,   _ForwardIterator2 __first2, _BinaryPredicate __pred)    {      // Efficiently compare identical prefixes:  O(N) if sequences      // have the same elements in the same order.      for (; __first1 != __last1; ++__first1, ++__first2)if (!bool(__pred(*__first1, *__first2)))  break;      if (__first1 == __last1)return true;      // Establish __last2 assuming equal ranges by iterating over the      // rest of the list.      _ForwardIterator2 __last2 = __first2;      std::advance(__last2, std::distance(__first1, __last1));      for (_ForwardIterator1 __scan = __first1; __scan != __last1; ++__scan){  using std::placeholders::_1;  if (__scan != _GLIBCXX_STD_A::find_if(__first1, __scan,std::bind(__pred, _1, *__scan)))    continue; // We've seen this one before.    auto __matches = std::count_if(__first2, __last2, std::bind(__pred, _1, *__scan));  if (0 == __matches      || std::count_if(__scan, __last1,       std::bind(__pred, _1, *__scan)) != __matches)    return false;}      return true;    }#ifdef _GLIBCXX_USE_C99_STDINT_TR1  /**   *  @brief Shuffle the elements of a sequence using a uniform random   *         number generator.   *  @ingroup mutating_algorithms   *  @param  __first   A forward iterator.   *  @param  __last    A forward iterator.   *  @param  __g       A UniformRandomNumberGenerator (26.5.1.3).   *  @return  Nothing.   *   *  Reorders the elements in the range @p [__first,__last) using @p __g to   *  provide random numbers.  */  template<typename _RandomAccessIterator,   typename _UniformRandomNumberGenerator>    void    shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,    _UniformRandomNumberGenerator&& __g)    {      // concept requirements      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<    _RandomAccessIterator>)      __glibcxx_requires_valid_range(__first, __last);      if (__first == __last)return;      typedef typename iterator_traits<_RandomAccessIterator>::difference_type_DistanceType;      typedef typename std::make_unsigned<_DistanceType>::type __ud_type;      typedef typename std::uniform_int_distribution<__ud_type> __distr_type;      typedef typename __distr_type::param_type __p_type;      __distr_type __d;      for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)std::iter_swap(__i, __first + __d(__g, __p_type(0, __i - __first)));    }#endif#endif // __GXX_EXPERIMENTAL_CXX0X___GLIBCXX_END_NAMESPACE_VERSION_GLIBCXX_BEGIN_NAMESPACE_ALGO  /**   *  @brief Apply a function to every element of a sequence.   *  @ingroup non_mutating_algorithms   *  @param  __first  An input iterator.   *  @param  __last   An input iterator.   *  @param  __f      A unary function object.   *  @return   @p __f (std::move(@p __f) in C++0x).   *   *  Applies the function object @p __f to each element in the range   *  @p [first,last).  @p __f must not modify the order of the sequence.   *  If @p __f has a return value it is ignored.  */  template<typename _InputIterator, typename _Function>    _Function    for_each(_InputIterator __first, _InputIterator __last, _Function __f)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_requires_valid_range(__first, __last);      for (; __first != __last; ++__first)__f(*__first);      return _GLIBCXX_MOVE(__f);    }  /**   *  @brief Find the first occurrence of a value in a sequence.   *  @ingroup non_mutating_algorithms   *  @param  __first  An input iterator.   *  @param  __last   An input iterator.   *  @param  __val    The value to find.   *  @return   The first iterator @c i in the range @p [__first,__last)   *  such that @c *i == @p __val, or @p __last if no such iterator exists.  */  template<typename _InputIterator, typename _Tp>    inline _InputIterator    find(_InputIterator __first, _InputIterator __last, const _Tp& __val)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_EqualOpConcept<typename iterator_traits<_InputIterator>::value_type, _Tp>)      __glibcxx_requires_valid_range(__first, __last);      return std::__find(__first, __last, __val,         std::__iterator_category(__first));    }  /**   *  @brief Find the first element in a sequence for which a   *         predicate is true.   *  @ingroup non_mutating_algorithms   *  @param  __first  An input iterator.   *  @param  __last   An input iterator.   *  @param  __pred   A predicate.   *  @return   The first iterator @c i in the range @p [__first,__last)   *  such that @p __pred(*i) is true, or @p __last if no such iterator exists.  */  template<typename _InputIterator, typename _Predicate>    inline _InputIterator    find_if(_InputIterator __first, _InputIterator __last,    _Predicate __pred)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,      typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      return std::__find_if(__first, __last, __pred,    std::__iterator_category(__first));    }  /**   *  @brief  Find element from a set in a sequence.   *  @ingroup non_mutating_algorithms   *  @param  __first1  Start of range to search.   *  @param  __last1   End of range to search.   *  @param  __first2  Start of match candidates.   *  @param  __last2   End of match candidates.   *  @return   The first iterator @c i in the range   *  @p [__first1,__last1) such that @c *i == @p *(i2) such that i2 is an   *  iterator in [__first2,__last2), or @p __last1 if no such iterator exists.   *   *  Searches the range @p [__first1,__last1) for an element that is   *  equal to some element in the range [__first2,__last2).  If   *  found, returns an iterator in the range [__first1,__last1),   *  otherwise returns @p __last1.  */  template<typename _InputIterator, typename _ForwardIterator>    _InputIterator    find_first_of(_InputIterator __first1, _InputIterator __last1,  _ForwardIterator __first2, _ForwardIterator __last2)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_EqualOpConcept<    typename iterator_traits<_InputIterator>::value_type,    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first1, __last1);      __glibcxx_requires_valid_range(__first2, __last2);      for (; __first1 != __last1; ++__first1)for (_ForwardIterator __iter = __first2; __iter != __last2; ++__iter)  if (*__first1 == *__iter)    return __first1;      return __last1;    }  /**   *  @brief  Find element from a set in a sequence using a predicate.   *  @ingroup non_mutating_algorithms   *  @param  __first1  Start of range to search.   *  @param  __last1   End of range to search.   *  @param  __first2  Start of match candidates.   *  @param  __last2   End of match candidates.   *  @param  __comp    Predicate to use.   *  @return   The first iterator @c i in the range   *  @p [__first1,__last1) such that @c comp(*i, @p *(i2)) is true   *  and i2 is an iterator in [__first2,__last2), or @p __last1 if no   *  such iterator exists.   *   *  Searches the range @p [__first1,__last1) for an element that is   *  equal to some element in the range [__first2,__last2).  If   *  found, returns an iterator in the range [__first1,__last1),   *  otherwise returns @p __last1.  */  template<typename _InputIterator, typename _ForwardIterator,   typename _BinaryPredicate>    _InputIterator    find_first_of(_InputIterator __first1, _InputIterator __last1,  _ForwardIterator __first2, _ForwardIterator __last2,  _BinaryPredicate __comp)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,    typename iterator_traits<_InputIterator>::value_type,    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first1, __last1);      __glibcxx_requires_valid_range(__first2, __last2);      for (; __first1 != __last1; ++__first1)for (_ForwardIterator __iter = __first2; __iter != __last2; ++__iter)  if (__comp(*__first1, *__iter))    return __first1;      return __last1;    }  /**   *  @brief Find two adjacent values in a sequence that are equal.   *  @ingroup non_mutating_algorithms   *  @param  __first  A forward iterator.   *  @param  __last   A forward iterator.   *  @return   The first iterator @c i such that @c i and @c i+1 are both   *  valid iterators in @p [__first,__last) and such that @c *i == @c *(i+1),   *  or @p __last if no such iterator exists.  */  template<typename _ForwardIterator>    _ForwardIterator    adjacent_find(_ForwardIterator __first, _ForwardIterator __last)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_EqualityComparableConcept<    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      if (__first == __last)return __last;      _ForwardIterator __next = __first;      while(++__next != __last){  if (*__first == *__next)    return __first;  __first = __next;}      return __last;    }  /**   *  @brief Find two adjacent values in a sequence using a predicate.   *  @ingroup non_mutating_algorithms   *  @param  __first         A forward iterator.   *  @param  __last          A forward iterator.   *  @param  __binary_pred   A binary predicate.   *  @return   The first iterator @c i such that @c i and @c i+1 are both   *  valid iterators in @p [__first,__last) and such that   *  @p __binary_pred(*i,*(i+1)) is true, or @p __last if no such iterator   *  exists.  */  template<typename _ForwardIterator, typename _BinaryPredicate>    _ForwardIterator    adjacent_find(_ForwardIterator __first, _ForwardIterator __last,  _BinaryPredicate __binary_pred)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,    typename iterator_traits<_ForwardIterator>::value_type,    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      if (__first == __last)return __last;      _ForwardIterator __next = __first;      while(++__next != __last){  if (__binary_pred(*__first, *__next))    return __first;  __first = __next;}      return __last;    }  /**   *  @brief Count the number of copies of a value in a sequence.   *  @ingroup non_mutating_algorithms   *  @param  __first  An input iterator.   *  @param  __last   An input iterator.   *  @param  __value  The value to be counted.   *  @return   The number of iterators @c i in the range @p [__first,__last)   *  for which @c *i == @p __value  */  template<typename _InputIterator, typename _Tp>    typename iterator_traits<_InputIterator>::difference_type    count(_InputIterator __first, _InputIterator __last, const _Tp& __value)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_EqualOpConcept<typename iterator_traits<_InputIterator>::value_type, _Tp>)      __glibcxx_requires_valid_range(__first, __last);      typename iterator_traits<_InputIterator>::difference_type __n = 0;      for (; __first != __last; ++__first)if (*__first == __value)  ++__n;      return __n;    }  /**   *  @brief Count the elements of a sequence for which a predicate is true.   *  @ingroup non_mutating_algorithms   *  @param  __first  An input iterator.   *  @param  __last   An input iterator.   *  @param  __pred   A predicate.   *  @return   The number of iterators @c i in the range @p [__first,__last)   *  for which @p __pred(*i) is true.  */  template<typename _InputIterator, typename _Predicate>    typename iterator_traits<_InputIterator>::difference_type    count_if(_InputIterator __first, _InputIterator __last, _Predicate __pred)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,    typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      typename iterator_traits<_InputIterator>::difference_type __n = 0;      for (; __first != __last; ++__first)if (__pred(*__first))  ++__n;      return __n;    }  /**   *  @brief Search a sequence for a matching sub-sequence.   *  @ingroup non_mutating_algorithms   *  @param  __first1  A forward iterator.   *  @param  __last1   A forward iterator.   *  @param  __first2  A forward iterator.   *  @param  __last2   A forward iterator.   *  @return The first iterator @c i in the range @p   *  [__first1,__last1-(__last2-__first2)) such that @c *(i+N) == @p   *  *(__first2+N) for each @c N in the range @p   *  [0,__last2-__first2), or @p __last1 if no such iterator exists.   *   *  Searches the range @p [__first1,__last1) for a sub-sequence that   *  compares equal value-by-value with the sequence given by @p   *  [__first2,__last2) and returns an iterator to the first element   *  of the sub-sequence, or @p __last1 if the sub-sequence is not   *  found.   *   *  Because the sub-sequence must lie completely within the range @p   *  [__first1,__last1) it must start at a position less than @p   *  __last1-(__last2-__first2) where @p __last2-__first2 is the   *  length of the sub-sequence.   *   *  This means that the returned iterator @c i will be in the range   *  @p [__first1,__last1-(__last2-__first2))  */  template<typename _ForwardIterator1, typename _ForwardIterator2>    _ForwardIterator1    search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,   _ForwardIterator2 __first2, _ForwardIterator2 __last2)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)      __glibcxx_function_requires(_EqualOpConcept<    typename iterator_traits<_ForwardIterator1>::value_type,    typename iterator_traits<_ForwardIterator2>::value_type>)      __glibcxx_requires_valid_range(__first1, __last1);      __glibcxx_requires_valid_range(__first2, __last2);      // Test for empty ranges      if (__first1 == __last1 || __first2 == __last2)return __first1;      // Test for a pattern of length 1.      _ForwardIterator2 __p1(__first2);      if (++__p1 == __last2)return _GLIBCXX_STD_A::find(__first1, __last1, *__first2);      // General case.      _ForwardIterator2 __p;      _ForwardIterator1 __current = __first1;      for (;;){  __first1 = _GLIBCXX_STD_A::find(__first1, __last1, *__first2);  if (__first1 == __last1)    return __last1;  __p = __p1;  __current = __first1;  if (++__current == __last1)    return __last1;  while (*__current == *__p)    {      if (++__p == __last2)return __first1;      if (++__current == __last1)return __last1;    }  ++__first1;}      return __first1;    }  /**   *  @brief Search a sequence for a matching sub-sequence using a predicate.   *  @ingroup non_mutating_algorithms   *  @param  __first1     A forward iterator.   *  @param  __last1      A forward iterator.   *  @param  __first2     A forward iterator.   *  @param  __last2      A forward iterator.   *  @param  __predicate  A binary predicate.   *  @return   The first iterator @c i in the range   *  @p [__first1,__last1-(__last2-__first2)) such that   *  @p __predicate(*(i+N),*(__first2+N)) is true for each @c N in the range   *  @p [0,__last2-__first2), or @p __last1 if no such iterator exists.   *   *  Searches the range @p [__first1,__last1) for a sub-sequence that   *  compares equal value-by-value with the sequence given by @p   *  [__first2,__last2), using @p __predicate to determine equality,   *  and returns an iterator to the first element of the   *  sub-sequence, or @p __last1 if no such iterator exists.   *   *  @see search(_ForwardIter1, _ForwardIter1, _ForwardIter2, _ForwardIter2)  */  template<typename _ForwardIterator1, typename _ForwardIterator2,   typename _BinaryPredicate>    _ForwardIterator1    search(_ForwardIterator1 __first1, _ForwardIterator1 __last1,   _ForwardIterator2 __first2, _ForwardIterator2 __last2,   _BinaryPredicate  __predicate)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator1>)      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator2>)      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,    typename iterator_traits<_ForwardIterator1>::value_type,    typename iterator_traits<_ForwardIterator2>::value_type>)      __glibcxx_requires_valid_range(__first1, __last1);      __glibcxx_requires_valid_range(__first2, __last2);      // Test for empty ranges      if (__first1 == __last1 || __first2 == __last2)return __first1;      // Test for a pattern of length 1.      _ForwardIterator2 __p1(__first2);      if (++__p1 == __last2){  while (__first1 != __last1 && !bool(__predicate(*__first1, *__first2)))    ++__first1;  return __first1;}      // General case.      _ForwardIterator2 __p;      _ForwardIterator1 __current = __first1;      for (;;){  while (__first1 != __last1 && !bool(__predicate(*__first1, *__first2)))    ++__first1;  if (__first1 == __last1)    return __last1;  __p = __p1;  __current = __first1;  if (++__current == __last1)    return __last1;  while (__predicate(*__current, *__p))    {      if (++__p == __last2)return __first1;      if (++__current == __last1)return __last1;    }  ++__first1;}      return __first1;    }  /**   *  @brief Search a sequence for a number of consecutive values.   *  @ingroup non_mutating_algorithms   *  @param  __first  A forward iterator.   *  @param  __last   A forward iterator.   *  @param  __count  The number of consecutive values.   *  @param  __val    The value to find.   *  @return The first iterator @c i in the range @p   *  [__first,__last-__count) such that @c *(i+N) == @p __val for   *  each @c N in the range @p [0,__count), or @p __last if no such   *  iterator exists.   *   *  Searches the range @p [__first,__last) for @p count consecutive elements   *  equal to @p __val.  */  template<typename _ForwardIterator, typename _Integer, typename _Tp>    _ForwardIterator    search_n(_ForwardIterator __first, _ForwardIterator __last,     _Integer __count, const _Tp& __val)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_EqualOpConcept<typename iterator_traits<_ForwardIterator>::value_type, _Tp>)      __glibcxx_requires_valid_range(__first, __last);      if (__count <= 0)return __first;      if (__count == 1)return _GLIBCXX_STD_A::find(__first, __last, __val);      return std::__search_n(__first, __last, __count, __val,     std::__iterator_category(__first));    }  /**   *  @brief Search a sequence for a number of consecutive values using a   *         predicate.   *  @ingroup non_mutating_algorithms   *  @param  __first        A forward iterator.   *  @param  __last         A forward iterator.   *  @param  __count        The number of consecutive values.   *  @param  __val          The value to find.   *  @param  __binary_pred  A binary predicate.   *  @return The first iterator @c i in the range @p   *  [__first,__last-__count) such that @p   *  __binary_pred(*(i+N),__val) is true for each @c N in the range   *  @p [0,__count), or @p __last if no such iterator exists.   *   *  Searches the range @p [__first,__last) for @p __count   *  consecutive elements for which the predicate returns true.  */  template<typename _ForwardIterator, typename _Integer, typename _Tp,           typename _BinaryPredicate>    _ForwardIterator    search_n(_ForwardIterator __first, _ForwardIterator __last,     _Integer __count, const _Tp& __val,     _BinaryPredicate __binary_pred)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_BinaryPredicate,    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)      __glibcxx_requires_valid_range(__first, __last);      if (__count <= 0)return __first;      if (__count == 1){  while (__first != __last && !bool(__binary_pred(*__first, __val)))    ++__first;  return __first;}      return std::__search_n(__first, __last, __count, __val, __binary_pred,     std::__iterator_category(__first));    }  /**   *  @brief Perform an operation on a sequence.   *  @ingroup mutating_algorithms   *  @param  __first     An input iterator.   *  @param  __last      An input iterator.   *  @param  __result    An output iterator.   *  @param  __unary_op  A unary operator.   *  @return   An output iterator equal to @p __result+(__last-__first).   *   *  Applies the operator to each element in the input range and assigns   *  the results to successive elements of the output sequence.   *  Evaluates @p *(__result+N)=unary_op(*(__first+N)) for each @c N in the   *  range @p [0,__last-__first).   *   *  @p unary_op must not alter its argument.  */  template<typename _InputIterator, typename _OutputIterator,   typename _UnaryOperation>    _OutputIterator    transform(_InputIterator __first, _InputIterator __last,      _OutputIterator __result, _UnaryOperation __unary_op)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,            // "the type returned by a _UnaryOperation"            __typeof__(__unary_op(*__first))>)      __glibcxx_requires_valid_range(__first, __last);      for (; __first != __last; ++__first, ++__result)*__result = __unary_op(*__first);      return __result;    }  /**   *  @brief Perform an operation on corresponding elements of two sequences.   *  @ingroup mutating_algorithms   *  @param  __first1     An input iterator.   *  @param  __last1      An input iterator.   *  @param  __first2     An input iterator.   *  @param  __result     An output iterator.   *  @param  __binary_op  A binary operator.   *  @return   An output iterator equal to @p result+(last-first).   *   *  Applies the operator to the corresponding elements in the two   *  input ranges and assigns the results to successive elements of the   *  output sequence.   *  Evaluates @p   *  *(__result+N)=__binary_op(*(__first1+N),*(__first2+N)) for each   *  @c N in the range @p [0,__last1-__first1).   *   *  @p binary_op must not alter either of its arguments.  */  template<typename _InputIterator1, typename _InputIterator2,   typename _OutputIterator, typename _BinaryOperation>    _OutputIterator    transform(_InputIterator1 __first1, _InputIterator1 __last1,      _InputIterator2 __first2, _OutputIterator __result,      _BinaryOperation __binary_op)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,            // "the type returned by a _BinaryOperation"            __typeof__(__binary_op(*__first1,*__first2))>)      __glibcxx_requires_valid_range(__first1, __last1);      for (; __first1 != __last1; ++__first1, ++__first2, ++__result)*__result = __binary_op(*__first1, *__first2);      return __result;    }  /**   *  @brief Replace each occurrence of one value in a sequence with another   *         value.   *  @ingroup mutating_algorithms   *  @param  __first      A forward iterator.   *  @param  __last       A forward iterator.   *  @param  __old_value  The value to be replaced.   *  @param  __new_value  The replacement value.   *  @return   replace() returns no value.   *   *  For each iterator @c i in the range @p [__first,__last) if @c *i ==   *  @p __old_value then the assignment @c *i = @p __new_value is performed.  */  template<typename _ForwardIterator, typename _Tp>    void    replace(_ForwardIterator __first, _ForwardIterator __last,    const _Tp& __old_value, const _Tp& __new_value)    {      // concept requirements      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<  _ForwardIterator>)      __glibcxx_function_requires(_EqualOpConcept<    typename iterator_traits<_ForwardIterator>::value_type, _Tp>)      __glibcxx_function_requires(_ConvertibleConcept<_Tp,    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      for (; __first != __last; ++__first)if (*__first == __old_value)  *__first = __new_value;    }  /**   *  @brief Replace each value in a sequence for which a predicate returns   *         true with another value.   *  @ingroup mutating_algorithms   *  @param  __first      A forward iterator.   *  @param  __last       A forward iterator.   *  @param  __pred       A predicate.   *  @param  __new_value  The replacement value.   *  @return   replace_if() returns no value.   *   *  For each iterator @c i in the range @p [__first,__last) if @p __pred(*i)   *  is true then the assignment @c *i = @p __new_value is performed.  */  template<typename _ForwardIterator, typename _Predicate, typename _Tp>    void    replace_if(_ForwardIterator __first, _ForwardIterator __last,       _Predicate __pred, const _Tp& __new_value)    {      // concept requirements      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<  _ForwardIterator>)      __glibcxx_function_requires(_ConvertibleConcept<_Tp,    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      for (; __first != __last; ++__first)if (__pred(*__first))  *__first = __new_value;    }  /**   *  @brief Assign the result of a function object to each value in a   *         sequence.   *  @ingroup mutating_algorithms   *  @param  __first  A forward iterator.   *  @param  __last   A forward iterator.   *  @param  __gen    A function object taking no arguments and returning   *                 std::iterator_traits<_ForwardIterator>::value_type   *  @return   generate() returns no value.   *   *  Performs the assignment @c *i = @p __gen() for each @c i in the range   *  @p [__first,__last).  */  template<typename _ForwardIterator, typename _Generator>    void    generate(_ForwardIterator __first, _ForwardIterator __last,     _Generator __gen)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_GeneratorConcept<_Generator,    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      for (; __first != __last; ++__first)*__first = __gen();    }  /**   *  @brief Assign the result of a function object to each value in a   *         sequence.   *  @ingroup mutating_algorithms   *  @param  __first  A forward iterator.   *  @param  __n      The length of the sequence.   *  @param  __gen    A function object taking no arguments and returning   *                 std::iterator_traits<_ForwardIterator>::value_type   *  @return   The end of the sequence, @p __first+__n   *   *  Performs the assignment @c *i = @p __gen() for each @c i in the range   *  @p [__first,__first+__n).   *   *  _GLIBCXX_RESOLVE_LIB_DEFECTS   *  DR 865. More algorithms that throw away information  */  template<typename _OutputIterator, typename _Size, typename _Generator>    _OutputIterator    generate_n(_OutputIterator __first, _Size __n, _Generator __gen)    {      // concept requirements      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,            // "the type returned by a _Generator"            __typeof__(__gen())>)      for (__decltype(__n + 0) __niter = __n;   __niter > 0; --__niter, ++__first)*__first = __gen();      return __first;    }  /**   *  @brief Copy a sequence, removing consecutive duplicate values.   *  @ingroup mutating_algorithms   *  @param  __first   An input iterator.   *  @param  __last    An input iterator.   *  @param  __result  An output iterator.   *  @return   An iterator designating the end of the resulting sequence.   *   *  Copies each element in the range @p [__first,__last) to the range   *  beginning at @p __result, except that only the first element is copied   *  from groups of consecutive elements that compare equal.   *  unique_copy() is stable, so the relative order of elements that are   *  copied is unchanged.   *   *  _GLIBCXX_RESOLVE_LIB_DEFECTS   *  DR 241. Does unique_copy() require CopyConstructible and Assignable?   *     *  _GLIBCXX_RESOLVE_LIB_DEFECTS   *  DR 538. 241 again: Does unique_copy() require CopyConstructible and    *  Assignable?  */  template<typename _InputIterator, typename _OutputIterator>    inline _OutputIterator    unique_copy(_InputIterator __first, _InputIterator __last,_OutputIterator __result)    {      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,    typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_function_requires(_EqualityComparableConcept<    typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      if (__first == __last)return __result;      return std::__unique_copy(__first, __last, __result,std::__iterator_category(__first),std::__iterator_category(__result));    }  /**   *  @brief Copy a sequence, removing consecutive values using a predicate.   *  @ingroup mutating_algorithms   *  @param  __first        An input iterator.   *  @param  __last         An input iterator.   *  @param  __result       An output iterator.   *  @param  __binary_pred  A binary predicate.   *  @return   An iterator designating the end of the resulting sequence.   *   *  Copies each element in the range @p [__first,__last) to the range   *  beginning at @p __result, except that only the first element is copied   *  from groups of consecutive elements for which @p __binary_pred returns   *  true.   *  unique_copy() is stable, so the relative order of elements that are   *  copied is unchanged.   *   *  _GLIBCXX_RESOLVE_LIB_DEFECTS   *  DR 241. Does unique_copy() require CopyConstructible and Assignable?  */  template<typename _InputIterator, typename _OutputIterator,   typename _BinaryPredicate>    inline _OutputIterator    unique_copy(_InputIterator __first, _InputIterator __last,_OutputIterator __result,_BinaryPredicate __binary_pred)    {      // concept requirements -- predicates checked later      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,    typename iterator_traits<_InputIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      if (__first == __last)return __result;      return std::__unique_copy(__first, __last, __result, __binary_pred,std::__iterator_category(__first),std::__iterator_category(__result));    }  /**   *  @brief Randomly shuffle the elements of a sequence.   *  @ingroup mutating_algorithms   *  @param  __first   A forward iterator.   *  @param  __last    A forward iterator.   *  @return  Nothing.   *   *  Reorder the elements in the range @p [__first,__last) using a random   *  distribution, so that every possible ordering of the sequence is   *  equally likely.  */  template<typename _RandomAccessIterator>    inline void    random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last)    {      // concept requirements      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<    _RandomAccessIterator>)      __glibcxx_requires_valid_range(__first, __last);      if (__first != __last)for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)  std::iter_swap(__i, __first + (std::rand() % ((__i - __first) + 1)));    }  /**   *  @brief Shuffle the elements of a sequence using a random number   *         generator.   *  @ingroup mutating_algorithms   *  @param  __first   A forward iterator.   *  @param  __last    A forward iterator.   *  @param  __rand    The RNG functor or function.   *  @return  Nothing.   *   *  Reorders the elements in the range @p [__first,__last) using @p __rand to   *  provide a random distribution. Calling @p __rand(N) for a positive   *  integer @p N should return a randomly chosen integer from the   *  range [0,N).  */  template<typename _RandomAccessIterator, typename _RandomNumberGenerator>    void    random_shuffle(_RandomAccessIterator __first, _RandomAccessIterator __last,#ifdef __GXX_EXPERIMENTAL_CXX0X__   _RandomNumberGenerator&& __rand)#else   _RandomNumberGenerator& __rand)#endif    {      // concept requirements      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<    _RandomAccessIterator>)      __glibcxx_requires_valid_range(__first, __last);      if (__first == __last)return;      for (_RandomAccessIterator __i = __first + 1; __i != __last; ++__i)std::iter_swap(__i, __first + __rand((__i - __first) + 1));    }  /**   *  @brief Move elements for which a predicate is true to the beginning   *         of a sequence.   *  @ingroup mutating_algorithms   *  @param  __first   A forward iterator.   *  @param  __last    A forward iterator.   *  @param  __pred    A predicate functor.   *  @return  An iterator @p middle such that @p __pred(i) is true for each   *  iterator @p i in the range @p [__first,middle) and false for each @p i   *  in the range @p [middle,__last).   *   *  @p __pred must not modify its operand. @p partition() does not preserve   *  the relative ordering of elements in each group, use   *  @p stable_partition() if this is needed.  */  template<typename _ForwardIterator, typename _Predicate>    inline _ForwardIterator    partition(_ForwardIterator __first, _ForwardIterator __last,      _Predicate   __pred)    {      // concept requirements      __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<  _ForwardIterator>)      __glibcxx_function_requires(_UnaryPredicateConcept<_Predicate,    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      return std::__partition(__first, __last, __pred,      std::__iterator_category(__first));    }  /**   *  @brief Sort the smallest elements of a sequence.   *  @ingroup sorting_algorithms   *  @param  __first   An iterator.   *  @param  __middle  Another iterator.   *  @param  __last    Another iterator.   *  @return  Nothing.   *   *  Sorts the smallest @p (__middle-__first) elements in the range   *  @p [first,last) and moves them to the range @p [__first,__middle). The   *  order of the remaining elements in the range @p [__middle,__last) is   *  undefined.   *  After the sort if @e i and @e j are iterators in the range   *  @p [__first,__middle) such that i precedes j and @e k is an iterator in   *  the range @p [__middle,__last) then *j<*i and *k<*i are both false.  */  template<typename _RandomAccessIterator>    inline void    partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last)    {      typedef typename iterator_traits<_RandomAccessIterator>::value_type_ValueType;      // concept requirements      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<    _RandomAccessIterator>)      __glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)      __glibcxx_requires_valid_range(__first, __middle);      __glibcxx_requires_valid_range(__middle, __last);      std::__heap_select(__first, __middle, __last);      std::sort_heap(__first, __middle);    }  /**   *  @brief Sort the smallest elements of a sequence using a predicate   *         for comparison.   *  @ingroup sorting_algorithms   *  @param  __first   An iterator.   *  @param  __middle  Another iterator.   *  @param  __last    Another iterator.   *  @param  __comp    A comparison functor.   *  @return  Nothing.   *   *  Sorts the smallest @p (__middle-__first) elements in the range   *  @p [__first,__last) and moves them to the range @p [__first,__middle). The   *  order of the remaining elements in the range @p [__middle,__last) is   *  undefined.   *  After the sort if @e i and @e j are iterators in the range   *  @p [__first,__middle) such that i precedes j and @e k is an iterator in   *  the range @p [__middle,__last) then @p *__comp(j,*i) and @p __comp(*k,*i)   *  are both false.  */  template<typename _RandomAccessIterator, typename _Compare>    inline void    partial_sort(_RandomAccessIterator __first, _RandomAccessIterator __middle, _RandomAccessIterator __last, _Compare __comp)    {      typedef typename iterator_traits<_RandomAccessIterator>::value_type_ValueType;      // concept requirements      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<    _RandomAccessIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _ValueType, _ValueType>)      __glibcxx_requires_valid_range(__first, __middle);      __glibcxx_requires_valid_range(__middle, __last);      std::__heap_select(__first, __middle, __last, __comp);      std::sort_heap(__first, __middle, __comp);    }  /**   *  @brief Sort a sequence just enough to find a particular position.   *  @ingroup sorting_algorithms   *  @param  __first   An iterator.   *  @param  __nth     Another iterator.   *  @param  __last    Another iterator.   *  @return  Nothing.   *   *  Rearranges the elements in the range @p [__first,__last) so that @p *__nth   *  is the same element that would have been in that position had the   *  whole sequence been sorted. The elements either side of @p *__nth are   *  not completely sorted, but for any iterator @e i in the range   *  @p [__first,__nth) and any iterator @e j in the range @p [__nth,__last) it   *  holds that *j < *i is false.  */  template<typename _RandomAccessIterator>    inline void    nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth,_RandomAccessIterator __last)    {      typedef typename iterator_traits<_RandomAccessIterator>::value_type_ValueType;      // concept requirements      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<  _RandomAccessIterator>)      __glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)      __glibcxx_requires_valid_range(__first, __nth);      __glibcxx_requires_valid_range(__nth, __last);      if (__first == __last || __nth == __last)return;      std::__introselect(__first, __nth, __last, std::__lg(__last - __first) * 2);    }  /**   *  @brief Sort a sequence just enough to find a particular position   *         using a predicate for comparison.   *  @ingroup sorting_algorithms   *  @param  __first   An iterator.   *  @param  __nth     Another iterator.   *  @param  __last    Another iterator.   *  @param  __comp    A comparison functor.   *  @return  Nothing.   *   *  Rearranges the elements in the range @p [__first,__last) so that @p *__nth   *  is the same element that would have been in that position had the   *  whole sequence been sorted. The elements either side of @p *__nth are   *  not completely sorted, but for any iterator @e i in the range   *  @p [__first,__nth) and any iterator @e j in the range @p [__nth,__last) it   *  holds that @p __comp(*j,*i) is false.  */  template<typename _RandomAccessIterator, typename _Compare>    inline void    nth_element(_RandomAccessIterator __first, _RandomAccessIterator __nth,_RandomAccessIterator __last, _Compare __comp)    {      typedef typename iterator_traits<_RandomAccessIterator>::value_type_ValueType;      // concept requirements      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<  _RandomAccessIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _ValueType, _ValueType>)      __glibcxx_requires_valid_range(__first, __nth);      __glibcxx_requires_valid_range(__nth, __last);      if (__first == __last || __nth == __last)return;      std::__introselect(__first, __nth, __last, std::__lg(__last - __first) * 2, __comp);    }  /**   *  @brief Sort the elements of a sequence.   *  @ingroup sorting_algorithms   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @return  Nothing.   *   *  Sorts the elements in the range @p [__first,__last) in ascending order,   *  such that for each iterator @e i in the range @p [__first,__last-1),     *  *(i+1)<*i is false.   *   *  The relative ordering of equivalent elements is not preserved, use   *  @p stable_sort() if this is needed.  */  template<typename _RandomAccessIterator>    inline void    sort(_RandomAccessIterator __first, _RandomAccessIterator __last)    {      typedef typename iterator_traits<_RandomAccessIterator>::value_type_ValueType;      // concept requirements      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<    _RandomAccessIterator>)      __glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)      __glibcxx_requires_valid_range(__first, __last);      if (__first != __last){  std::__introsort_loop(__first, __last,std::__lg(__last - __first) * 2);  std::__final_insertion_sort(__first, __last);}    }  /**   *  @brief Sort the elements of a sequence using a predicate for comparison.   *  @ingroup sorting_algorithms   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @param  __comp    A comparison functor.   *  @return  Nothing.   *   *  Sorts the elements in the range @p [__first,__last) in ascending order,   *  such that @p __comp(*(i+1),*i) is false for every iterator @e i in the   *  range @p [__first,__last-1).   *   *  The relative ordering of equivalent elements is not preserved, use   *  @p stable_sort() if this is needed.  */  template<typename _RandomAccessIterator, typename _Compare>    inline void    sort(_RandomAccessIterator __first, _RandomAccessIterator __last, _Compare __comp)    {      typedef typename iterator_traits<_RandomAccessIterator>::value_type_ValueType;      // concept requirements      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<    _RandomAccessIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare, _ValueType,  _ValueType>)      __glibcxx_requires_valid_range(__first, __last);      if (__first != __last){  std::__introsort_loop(__first, __last,std::__lg(__last - __first) * 2, __comp);  std::__final_insertion_sort(__first, __last, __comp);}    }  /**   *  @brief Merges two sorted ranges.   *  @ingroup sorting_algorithms   *  @param  __first1  An iterator.   *  @param  __first2  Another iterator.   *  @param  __last1   Another iterator.   *  @param  __last2   Another iterator.   *  @param  __result  An iterator pointing to the end of the merged range.   *  @return         An iterator pointing to the first element <em>not less   *                  than</em> @e val.   *   *  Merges the ranges @p [__first1,__last1) and @p [__first2,__last2) into   *  the sorted range @p [__result, __result + (__last1-__first1) +   *  (__last2-__first2)).  Both input ranges must be sorted, and the   *  output range must not overlap with either of the input ranges.   *  The sort is @e stable, that is, for equivalent elements in the   *  two ranges, elements from the first range will always come   *  before elements from the second.  */  template<typename _InputIterator1, typename _InputIterator2,   typename _OutputIterator>    _OutputIterator    merge(_InputIterator1 __first1, _InputIterator1 __last1,  _InputIterator2 __first2, _InputIterator2 __last2,  _OutputIterator __result)    {      typedef typename iterator_traits<_InputIterator1>::value_type_ValueType1;      typedef typename iterator_traits<_InputIterator2>::value_type_ValueType2;      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,  _ValueType1>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,  _ValueType2>)      __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)      __glibcxx_requires_sorted_set(__first1, __last1, __first2);      __glibcxx_requires_sorted_set(__first2, __last2, __first1);      while (__first1 != __last1 && __first2 != __last2){  if (*__first2 < *__first1)    {      *__result = *__first2;      ++__first2;    }  else    {      *__result = *__first1;      ++__first1;    }  ++__result;}      return std::copy(__first2, __last2, std::copy(__first1, __last1,    __result));    }  /**   *  @brief Merges two sorted ranges.   *  @ingroup sorting_algorithms   *  @param  __first1  An iterator.   *  @param  __first2  Another iterator.   *  @param  __last1   Another iterator.   *  @param  __last2   Another iterator.   *  @param  __result  An iterator pointing to the end of the merged range.   *  @param  __comp    A functor to use for comparisons.   *  @return         An iterator pointing to the first element "not less   *                  than" @e val.   *   *  Merges the ranges @p [__first1,__last1) and @p [__first2,__last2) into   *  the sorted range @p [__result, __result + (__last1-__first1) +   *  (__last2-__first2)).  Both input ranges must be sorted, and the   *  output range must not overlap with either of the input ranges.   *  The sort is @e stable, that is, for equivalent elements in the   *  two ranges, elements from the first range will always come   *  before elements from the second.   *   *  The comparison function should have the same effects on ordering as   *  the function used for the initial sort.  */  template<typename _InputIterator1, typename _InputIterator2,   typename _OutputIterator, typename _Compare>    _OutputIterator    merge(_InputIterator1 __first1, _InputIterator1 __last1,  _InputIterator2 __first2, _InputIterator2 __last2,  _OutputIterator __result, _Compare __comp)    {      typedef typename iterator_traits<_InputIterator1>::value_type_ValueType1;      typedef typename iterator_traits<_InputIterator2>::value_type_ValueType2;      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,  _ValueType1>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,  _ValueType2>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _ValueType2, _ValueType1>)      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);      while (__first1 != __last1 && __first2 != __last2){  if (__comp(*__first2, *__first1))    {      *__result = *__first2;      ++__first2;    }  else    {      *__result = *__first1;      ++__first1;    }  ++__result;}      return std::copy(__first2, __last2, std::copy(__first1, __last1,    __result));    }  /**   *  @brief Sort the elements of a sequence, preserving the relative order   *         of equivalent elements.   *  @ingroup sorting_algorithms   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @return  Nothing.   *   *  Sorts the elements in the range @p [__first,__last) in ascending order,   *  such that for each iterator @p i in the range @p [__first,__last-1),   *  @p *(i+1)<*i is false.   *   *  The relative ordering of equivalent elements is preserved, so any two   *  elements @p x and @p y in the range @p [__first,__last) such that   *  @p x<y is false and @p y<x is false will have the same relative   *  ordering after calling @p stable_sort().  */  template<typename _RandomAccessIterator>    inline void    stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last)    {      typedef typename iterator_traits<_RandomAccessIterator>::value_type_ValueType;      typedef typename iterator_traits<_RandomAccessIterator>::difference_type_DistanceType;      // concept requirements      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<    _RandomAccessIterator>)      __glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)      __glibcxx_requires_valid_range(__first, __last);      _Temporary_buffer<_RandomAccessIterator, _ValueType> __buf(__first, __last);      if (__buf.begin() == 0)std::__inplace_stable_sort(__first, __last);      elsestd::__stable_sort_adaptive(__first, __last, __buf.begin(),    _DistanceType(__buf.size()));    }  /**   *  @brief Sort the elements of a sequence using a predicate for comparison,   *         preserving the relative order of equivalent elements.   *  @ingroup sorting_algorithms   *  @param  __first   An iterator.   *  @param  __last    Another iterator.   *  @param  __comp    A comparison functor.   *  @return  Nothing.   *   *  Sorts the elements in the range @p [__first,__last) in ascending order,   *  such that for each iterator @p i in the range @p [__first,__last-1),   *  @p __comp(*(i+1),*i) is false.   *   *  The relative ordering of equivalent elements is preserved, so any two   *  elements @p x and @p y in the range @p [__first,__last) such that   *  @p __comp(x,y) is false and @p __comp(y,x) is false will have the same   *  relative ordering after calling @p stable_sort().  */  template<typename _RandomAccessIterator, typename _Compare>    inline void    stable_sort(_RandomAccessIterator __first, _RandomAccessIterator __last,_Compare __comp)    {      typedef typename iterator_traits<_RandomAccessIterator>::value_type_ValueType;      typedef typename iterator_traits<_RandomAccessIterator>::difference_type_DistanceType;      // concept requirements      __glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<    _RandomAccessIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _ValueType,  _ValueType>)      __glibcxx_requires_valid_range(__first, __last);      _Temporary_buffer<_RandomAccessIterator, _ValueType> __buf(__first, __last);      if (__buf.begin() == 0)std::__inplace_stable_sort(__first, __last, __comp);      elsestd::__stable_sort_adaptive(__first, __last, __buf.begin(),    _DistanceType(__buf.size()), __comp);    }  /**   *  @brief Return the union of two sorted ranges.   *  @ingroup set_algorithms   *  @param  __first1  Start of first range.   *  @param  __last1   End of first range.   *  @param  __first2  Start of second range.   *  @param  __last2   End of second range.   *  @return  End of the output range.   *  @ingroup set_algorithms   *   *  This operation iterates over both ranges, copying elements present in   *  each range in order to the output range.  Iterators increment for each   *  range.  When the current element of one range is less than the other,   *  that element is copied and the iterator advanced.  If an element is   *  contained in both ranges, the element from the first range is copied and   *  both ranges advance.  The output range may not overlap either input   *  range.  */  template<typename _InputIterator1, typename _InputIterator2,   typename _OutputIterator>    _OutputIterator    set_union(_InputIterator1 __first1, _InputIterator1 __last1,      _InputIterator2 __first2, _InputIterator2 __last2,      _OutputIterator __result)    {      typedef typename iterator_traits<_InputIterator1>::value_type_ValueType1;      typedef typename iterator_traits<_InputIterator2>::value_type_ValueType2;      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,  _ValueType1>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,  _ValueType2>)      __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)      __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)      __glibcxx_requires_sorted_set(__first1, __last1, __first2);      __glibcxx_requires_sorted_set(__first2, __last2, __first1);      while (__first1 != __last1 && __first2 != __last2){  if (*__first1 < *__first2)    {      *__result = *__first1;      ++__first1;    }  else if (*__first2 < *__first1)    {      *__result = *__first2;      ++__first2;    }  else    {      *__result = *__first1;      ++__first1;      ++__first2;    }  ++__result;}      return std::copy(__first2, __last2, std::copy(__first1, __last1,    __result));    }  /**   *  @brief Return the union of two sorted ranges using a comparison functor.   *  @ingroup set_algorithms   *  @param  __first1  Start of first range.   *  @param  __last1   End of first range.   *  @param  __first2  Start of second range.   *  @param  __last2   End of second range.   *  @param  __comp    The comparison functor.   *  @return  End of the output range.   *  @ingroup set_algorithms   *   *  This operation iterates over both ranges, copying elements present in   *  each range in order to the output range.  Iterators increment for each   *  range.  When the current element of one range is less than the other   *  according to @p __comp, that element is copied and the iterator advanced.   *  If an equivalent element according to @p __comp is contained in both   *  ranges, the element from the first range is copied and both ranges   *  advance.  The output range may not overlap either input range.  */  template<typename _InputIterator1, typename _InputIterator2,   typename _OutputIterator, typename _Compare>    _OutputIterator    set_union(_InputIterator1 __first1, _InputIterator1 __last1,      _InputIterator2 __first2, _InputIterator2 __last2,      _OutputIterator __result, _Compare __comp)    {      typedef typename iterator_traits<_InputIterator1>::value_type_ValueType1;      typedef typename iterator_traits<_InputIterator2>::value_type_ValueType2;      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,  _ValueType1>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,  _ValueType2>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _ValueType1, _ValueType2>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _ValueType2, _ValueType1>)      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);      while (__first1 != __last1 && __first2 != __last2){  if (__comp(*__first1, *__first2))    {      *__result = *__first1;      ++__first1;    }  else if (__comp(*__first2, *__first1))    {      *__result = *__first2;      ++__first2;    }  else    {      *__result = *__first1;      ++__first1;      ++__first2;    }  ++__result;}      return std::copy(__first2, __last2, std::copy(__first1, __last1,    __result));    }  /**   *  @brief Return the intersection of two sorted ranges.   *  @ingroup set_algorithms   *  @param  __first1  Start of first range.   *  @param  __last1   End of first range.   *  @param  __first2  Start of second range.   *  @param  __last2   End of second range.   *  @return  End of the output range.   *  @ingroup set_algorithms   *   *  This operation iterates over both ranges, copying elements present in   *  both ranges in order to the output range.  Iterators increment for each   *  range.  When the current element of one range is less than the other,   *  that iterator advances.  If an element is contained in both ranges, the   *  element from the first range is copied and both ranges advance.  The   *  output range may not overlap either input range.  */  template<typename _InputIterator1, typename _InputIterator2,   typename _OutputIterator>    _OutputIterator    set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,     _InputIterator2 __first2, _InputIterator2 __last2,     _OutputIterator __result)    {      typedef typename iterator_traits<_InputIterator1>::value_type_ValueType1;      typedef typename iterator_traits<_InputIterator2>::value_type_ValueType2;      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,  _ValueType1>)      __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)      __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)      __glibcxx_requires_sorted_set(__first1, __last1, __first2);      __glibcxx_requires_sorted_set(__first2, __last2, __first1);      while (__first1 != __last1 && __first2 != __last2)if (*__first1 < *__first2)  ++__first1;else if (*__first2 < *__first1)  ++__first2;else  {    *__result = *__first1;    ++__first1;    ++__first2;    ++__result;  }      return __result;    }  /**   *  @brief Return the intersection of two sorted ranges using comparison   *  functor.   *  @ingroup set_algorithms   *  @param  __first1  Start of first range.   *  @param  __last1   End of first range.   *  @param  __first2  Start of second range.   *  @param  __last2   End of second range.   *  @param  __comp    The comparison functor.   *  @return  End of the output range.   *  @ingroup set_algorithms   *   *  This operation iterates over both ranges, copying elements present in   *  both ranges in order to the output range.  Iterators increment for each   *  range.  When the current element of one range is less than the other   *  according to @p __comp, that iterator advances.  If an element is   *  contained in both ranges according to @p __comp, the element from the   *  first range is copied and both ranges advance.  The output range may not   *  overlap either input range.  */  template<typename _InputIterator1, typename _InputIterator2,   typename _OutputIterator, typename _Compare>    _OutputIterator    set_intersection(_InputIterator1 __first1, _InputIterator1 __last1,     _InputIterator2 __first2, _InputIterator2 __last2,     _OutputIterator __result, _Compare __comp)    {      typedef typename iterator_traits<_InputIterator1>::value_type_ValueType1;      typedef typename iterator_traits<_InputIterator2>::value_type_ValueType2;      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,  _ValueType1>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _ValueType1, _ValueType2>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _ValueType2, _ValueType1>)      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);      while (__first1 != __last1 && __first2 != __last2)if (__comp(*__first1, *__first2))  ++__first1;else if (__comp(*__first2, *__first1))  ++__first2;else  {    *__result = *__first1;    ++__first1;    ++__first2;    ++__result;  }      return __result;    }  /**   *  @brief Return the difference of two sorted ranges.   *  @ingroup set_algorithms   *  @param  __first1  Start of first range.   *  @param  __last1   End of first range.   *  @param  __first2  Start of second range.   *  @param  __last2   End of second range.   *  @return  End of the output range.   *  @ingroup set_algorithms   *   *  This operation iterates over both ranges, copying elements present in   *  the first range but not the second in order to the output range.   *  Iterators increment for each range.  When the current element of the   *  first range is less than the second, that element is copied and the   *  iterator advances.  If the current element of the second range is less,   *  the iterator advances, but no element is copied.  If an element is   *  contained in both ranges, no elements are copied and both ranges   *  advance.  The output range may not overlap either input range.  */  template<typename _InputIterator1, typename _InputIterator2,   typename _OutputIterator>    _OutputIterator    set_difference(_InputIterator1 __first1, _InputIterator1 __last1,   _InputIterator2 __first2, _InputIterator2 __last2,   _OutputIterator __result)    {      typedef typename iterator_traits<_InputIterator1>::value_type_ValueType1;      typedef typename iterator_traits<_InputIterator2>::value_type_ValueType2;      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,  _ValueType1>)      __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)      __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)      __glibcxx_requires_sorted_set(__first1, __last1, __first2);      __glibcxx_requires_sorted_set(__first2, __last2, __first1);      while (__first1 != __last1 && __first2 != __last2)if (*__first1 < *__first2)  {    *__result = *__first1;    ++__first1;    ++__result;  }else if (*__first2 < *__first1)  ++__first2;else  {    ++__first1;    ++__first2;  }      return std::copy(__first1, __last1, __result);    }  /**   *  @brief  Return the difference of two sorted ranges using comparison   *  functor.   *  @ingroup set_algorithms   *  @param  __first1  Start of first range.   *  @param  __last1   End of first range.   *  @param  __first2  Start of second range.   *  @param  __last2   End of second range.   *  @param  __comp    The comparison functor.   *  @return  End of the output range.   *  @ingroup set_algorithms   *   *  This operation iterates over both ranges, copying elements present in   *  the first range but not the second in order to the output range.   *  Iterators increment for each range.  When the current element of the   *  first range is less than the second according to @p __comp, that element   *  is copied and the iterator advances.  If the current element of the   *  second range is less, no element is copied and the iterator advances.   *  If an element is contained in both ranges according to @p __comp, no   *  elements are copied and both ranges advance.  The output range may not   *  overlap either input range.  */  template<typename _InputIterator1, typename _InputIterator2,   typename _OutputIterator, typename _Compare>    _OutputIterator    set_difference(_InputIterator1 __first1, _InputIterator1 __last1,   _InputIterator2 __first2, _InputIterator2 __last2,   _OutputIterator __result, _Compare __comp)    {      typedef typename iterator_traits<_InputIterator1>::value_type_ValueType1;      typedef typename iterator_traits<_InputIterator2>::value_type_ValueType2;      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,  _ValueType1>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _ValueType1, _ValueType2>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _ValueType2, _ValueType1>)      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);      while (__first1 != __last1 && __first2 != __last2)if (__comp(*__first1, *__first2))  {    *__result = *__first1;    ++__first1;    ++__result;  }else if (__comp(*__first2, *__first1))  ++__first2;else  {    ++__first1;    ++__first2;  }      return std::copy(__first1, __last1, __result);    }  /**   *  @brief  Return the symmetric difference of two sorted ranges.   *  @ingroup set_algorithms   *  @param  __first1  Start of first range.   *  @param  __last1   End of first range.   *  @param  __first2  Start of second range.   *  @param  __last2   End of second range.   *  @return  End of the output range.   *  @ingroup set_algorithms   *   *  This operation iterates over both ranges, copying elements present in   *  one range but not the other in order to the output range.  Iterators   *  increment for each range.  When the current element of one range is less   *  than the other, that element is copied and the iterator advances.  If an   *  element is contained in both ranges, no elements are copied and both   *  ranges advance.  The output range may not overlap either input range.  */  template<typename _InputIterator1, typename _InputIterator2,   typename _OutputIterator>    _OutputIterator    set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,     _InputIterator2 __first2, _InputIterator2 __last2,     _OutputIterator __result)    {      typedef typename iterator_traits<_InputIterator1>::value_type_ValueType1;      typedef typename iterator_traits<_InputIterator2>::value_type_ValueType2;      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,  _ValueType1>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,  _ValueType2>)      __glibcxx_function_requires(_LessThanOpConcept<_ValueType1, _ValueType2>)      __glibcxx_function_requires(_LessThanOpConcept<_ValueType2, _ValueType1>)      __glibcxx_requires_sorted_set(__first1, __last1, __first2);      __glibcxx_requires_sorted_set(__first2, __last2, __first1);      while (__first1 != __last1 && __first2 != __last2)if (*__first1 < *__first2)  {    *__result = *__first1;    ++__first1;    ++__result;  }else if (*__first2 < *__first1)  {    *__result = *__first2;    ++__first2;    ++__result;  }else  {    ++__first1;    ++__first2;  }      return std::copy(__first2, __last2, std::copy(__first1,    __last1, __result));    }  /**   *  @brief  Return the symmetric difference of two sorted ranges using   *  comparison functor.   *  @ingroup set_algorithms   *  @param  __first1  Start of first range.   *  @param  __last1   End of first range.   *  @param  __first2  Start of second range.   *  @param  __last2   End of second range.   *  @param  __comp    The comparison functor.   *  @return  End of the output range.   *  @ingroup set_algorithms   *   *  This operation iterates over both ranges, copying elements present in   *  one range but not the other in order to the output range.  Iterators   *  increment for each range.  When the current element of one range is less   *  than the other according to @p comp, that element is copied and the   *  iterator advances.  If an element is contained in both ranges according   *  to @p __comp, no elements are copied and both ranges advance.  The output   *  range may not overlap either input range.  */  template<typename _InputIterator1, typename _InputIterator2,   typename _OutputIterator, typename _Compare>    _OutputIterator    set_symmetric_difference(_InputIterator1 __first1, _InputIterator1 __last1,     _InputIterator2 __first2, _InputIterator2 __last2,     _OutputIterator __result,     _Compare __comp)    {      typedef typename iterator_traits<_InputIterator1>::value_type_ValueType1;      typedef typename iterator_traits<_InputIterator2>::value_type_ValueType2;      // concept requirements      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,  _ValueType1>)      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,  _ValueType2>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _ValueType1, _ValueType2>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,  _ValueType2, _ValueType1>)      __glibcxx_requires_sorted_set_pred(__first1, __last1, __first2, __comp);      __glibcxx_requires_sorted_set_pred(__first2, __last2, __first1, __comp);      while (__first1 != __last1 && __first2 != __last2)if (__comp(*__first1, *__first2))  {    *__result = *__first1;    ++__first1;    ++__result;  }else if (__comp(*__first2, *__first1))  {    *__result = *__first2;    ++__first2;    ++__result;  }else  {    ++__first1;    ++__first2;  }      return std::copy(__first2, __last2,        std::copy(__first1, __last1, __result));    }  /**   *  @brief  Return the minimum element in a range.   *  @ingroup sorting_algorithms   *  @param  __first  Start of range.   *  @param  __last   End of range.   *  @return  Iterator referencing the first instance of the smallest value.  */  template<typename _ForwardIterator>    _ForwardIterator    min_element(_ForwardIterator __first, _ForwardIterator __last)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_LessThanComparableConcept<    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      if (__first == __last)return __first;      _ForwardIterator __result = __first;      while (++__first != __last)if (*__first < *__result)  __result = __first;      return __result;    }  /**   *  @brief  Return the minimum element in a range using comparison functor.   *  @ingroup sorting_algorithms   *  @param  __first  Start of range.   *  @param  __last   End of range.   *  @param  __comp   Comparison functor.   *  @return  Iterator referencing the first instance of the smallest value   *  according to __comp.  */  template<typename _ForwardIterator, typename _Compare>    _ForwardIterator    min_element(_ForwardIterator __first, _ForwardIterator __last,_Compare __comp)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,    typename iterator_traits<_ForwardIterator>::value_type,    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      if (__first == __last)return __first;      _ForwardIterator __result = __first;      while (++__first != __last)if (__comp(*__first, *__result))  __result = __first;      return __result;    }  /**   *  @brief  Return the maximum element in a range.   *  @ingroup sorting_algorithms   *  @param  __first  Start of range.   *  @param  __last   End of range.   *  @return  Iterator referencing the first instance of the largest value.  */  template<typename _ForwardIterator>    _ForwardIterator    max_element(_ForwardIterator __first, _ForwardIterator __last)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_LessThanComparableConcept<    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      if (__first == __last)return __first;      _ForwardIterator __result = __first;      while (++__first != __last)if (*__result < *__first)  __result = __first;      return __result;    }  /**   *  @brief  Return the maximum element in a range using comparison functor.   *  @ingroup sorting_algorithms   *  @param  __first  Start of range.   *  @param  __last   End of range.   *  @param  __comp   Comparison functor.   *  @return  Iterator referencing the first instance of the largest value   *  according to __comp.  */  template<typename _ForwardIterator, typename _Compare>    _ForwardIterator    max_element(_ForwardIterator __first, _ForwardIterator __last,_Compare __comp)    {      // concept requirements      __glibcxx_function_requires(_ForwardIteratorConcept<_ForwardIterator>)      __glibcxx_function_requires(_BinaryPredicateConcept<_Compare,    typename iterator_traits<_ForwardIterator>::value_type,    typename iterator_traits<_ForwardIterator>::value_type>)      __glibcxx_requires_valid_range(__first, __last);      if (__first == __last) return __first;      _ForwardIterator __result = __first;      while (++__first != __last)if (__comp(*__result, *__first))  __result = __first;      return __result;    }_GLIBCXX_END_NAMESPACE_ALGO} // namespace std#endif /* _STL_ALGO_H */</span>