STL_算法_重排和分区(random_shuffle、partition、stable_partition)

C++ Primer 学习中。。。

 

简单记录下我的学习过程 (代码为主)

//所有容器适用//所有容器适用
random_shuffle(b,e)       //随机重排
random_shuffle(b,e,rand)
partition(b,e,p)          //分区(不稳定)
stable_partition(b,e,p)   //稳定分区，相对顺序不变。
//返回值，为第一个分区的最后一个的后一个位置，也可以说是下个分区的起始位置！

/**------http://blog.csdn.net/u010579068------**/#include<iostream>#include<cstdio>#include<string>#include<vector>#include<list>#include<ctime>#include<deque>#include<algorithm>using namespace std;/*****************************************//所有容器适用random_shuffle(b,e)         //随机重排random_shuffle(b,e,rand)partition(b,e,p)            //分区(不稳定)stable_partition(b,e,p)     //稳定分区，相对顺序不变。                            //返回值，为第一个分区的最后一个的后一个位置，也可以说是下个分区的起始位置！*****************************************//**--------------------------------------------------------------------------------------------------------------------------------------------------------------------**//*************************************************************************************std::random_shuffle                  所有排序容器适用                       algorithm--------------------------------------------------------------------------------------template <class RandomAccessIterator>  void random_shuffle ( RandomAccessIterator first, RandomAccessIterator last );template <class RandomAccessIterator, class RandomNumberGenerator>  void random_shuffle ( RandomAccessIterator first, RandomAccessIterator last,                        RandomNumberGenerator& rand );//eg：template <class RandomAccessIterator, class RandomNumberGenerator>  void random_shuffle ( RandomAccessIterator first, RandomAccessIterator last,                        RandomNumberGenerator& rand ){  iterator_traits<RandomAccessIterator>::difference_type i, n;  n = (last-first);  for (i=n-1; i>0; --i) swap (first[i],first[rand(i+1)]);}*************************************************************************************//*************************************************************************************std::partition                   所有排序容器适用                           algorithm--------------------------------------------------------------------------------------template <class BidirectionalIterator, class Predicate>  BidirectionalIterator partition ( BidirectionalIterator first,                                    BidirectionalIterator last, Predicate pred );//eg：template <class BidirectionalIterator, class Predicate>  BidirectionalIterator partition ( BidirectionalIterator first,                                    BidirectionalIterator last, Predicate pred ){  while (true)  {    while (first!=last && pred(*first)) ++first;    if (first==last--) break;    while (first!=last && !pred(*last)) --last;    if (first==last) break;    swap (*first++,*last);  }  return first;}*************************************************************************************//*************************************************************************************std::stable_partition                 所有排序容器适用                     algorithm--------------------------------------------------------------------------------------template <class BidirectionalIterator, class Predicate>  BidirectionalIterator stable_partition ( BidirectionalIterator first,                                           BidirectionalIterator last,                                           Predicate pred );//eg：*************************************************************************************/// random generator function:ptrdiff_t myrandom (ptrdiff_t i){    return rand()%i;}// pointer object to it:ptrdiff_t (*p_myrandom)(ptrdiff_t) = myrandom;template <typename T>void Print(T& V){    typename T::iterator iter=V.begin();    while(iter != V.end())    {        cout<< *iter++ << " ";    }    cout<<endl;}int main (){    /**---------------------随机重排----------------------**/    srand (unsigned(time(NULL)));    vector<int> myvector;    vector<int>::iterator it;    // set some values:    for (int i=1; i<10; ++i) myvector.push_back(i); // 1 2 3 4 5 6 7 8 9    // using built-in random generator:    random_shuffle ( myvector.begin(), myvector.end() );    cout << "myvector random_shuffle 1 contains:";    Print(myvector);    // using myrandom:    random_shuffle ( myvector.begin(), myvector.end(), p_myrandom);    // print out content:    cout << "myvector random_shuffle 2 contains:";    Print(myvector);    cout << endl;    /**-----------------------分区------------------------**/    deque<int> mydeque;    deque<int>::iterator id, bound;    // set some values:    for (int i=1; i<10; ++i) mydeque.push_back(i); // 1 2 3 4 5 6 7 8 9    bound = partition (mydeque.begin(), mydeque.end(), bind2nd(modulus<int>(),2));    // print out content:    cout << "odd members:";    for (id=mydeque.begin(); id!=bound; ++id)        cout << " " << *id;    cout << "\neven members:";    for (id=bound; id!=mydeque.end(); ++id)        cout << " " << *id;    cout << endl << endl;    /**---------------------稳定分区----------------------**/    int m[]={1,4,3,2,9,6,7,8,5};    list<int> mylist(m,m+9);    list<int>::iterator il, lbound;    // set some values://    for (int i=1; i<10; ++i) mylist.push_back(i); // 1 2 3 4 5 6 7 8 9    lbound = stable_partition (mylist.begin(), mylist.end(), bind2nd(modulus<int>(),2));    // print out content:    cout << "odd members:";    for (il=mylist.begin(); il!=lbound; ++il)        cout << " " << *il;    cout << "\neven members:";    for (il=lbound; il!=mylist.end(); ++il)        cout << " " << *il;    cout << endl;    return 0;}

myvector random_shuffle 1 contains:6 4 9 7 1 8 3 5 2myvector random_shuffle 2 contains:3 4 2 6 9 7 8 5 1odd members: 1 9 3 7 5even members: 6 4 8 2odd members: 1 3 9 7 5even members: 4 2 6 8