试题:实现堆

堆的实现:

#include <vector>#include <iostream>using namespace std;template <typename RandomAccessIterator, typename T, typename CompareFunc>void __push__heap(RandomAccessIterator start, RandomAccessIterator end,                  T *, CompareFunc comp){if (end - start == 1){return;}unsigned int parent = end - start - 1;while (parent > 0){parent = (parent - 1) / 2;unsigned int lchild = parent * 2 + 1;unsigned int rchild = parent * 2 + 2;unsigned int max = lchild;if (start + rchild < end){max = comp(*(start + lchild), *(start + rchild))                ? rchild                : lchild;}if (comp(*(start + parent), *(start + max))){T temp(*(start + parent));*(start + parent) = *(start + max);*(start + max) = temp;}else{return;}}}template <typename RandomAccessIterator, typename CompareFunc>void push__heap(RandomAccessIterator start, RandomAccessIterator end,                CompareFunc comp){    __push__heap(start, end, &*start, comp);}template <typename RandomAccessIterator, typename T>void __push__heap(RandomAccessIterator start, RandomAccessIterator end,                  T *){    push__heap(start, end, less<T>());}template <typename RandomAccessIterator>void push__heap(RandomAccessIterator start, RandomAccessIterator end){    __push__heap(start, end, &*start);}template <typename RandomAccessIterator, typename T, typename CompareFunc>void __adjust__heap(RandomAccessIterator start, RandomAccessIterator end,                    unsigned int parent, T *, CompareFunc comp){    unsigned int last = end - start;    unsigned int lchild = parent * 2 + 1;    unsigned int rchild = parent * 2 + 2;while (lchild < last){        unsigned int max = lchild;if (rchild < last){max = comp(*(start + lchild), *(start + rchild))                ? rchild                : lchild;}if (comp(*(start + parent), *(start + max))){T temp(*(start + parent));*(start + parent) = *(start + max);*(start + max) = temp;parent = max;lchild = parent * 2 + 1;rchild = parent * 2 + 2;}else{return;}}}template <typename RandomAccessIterator, typename T, typename CompareFunc>void __pop__heap(RandomAccessIterator start, RandomAccessIterator end,                 T *, CompareFunc comp){--end;T temp(*start);*start = *end;*end = temp;__adjust__heap(start, end, 0, &*start, comp);}template <typename RandomAccessIterator, typename CompareFunc>void pop__heap(RandomAccessIterator start, RandomAccessIterator end,               CompareFunc comp){__pop__heap(start, end, &*start, comp);}template <typename RandomAccessIterator, typename T>void __pop__heap(RandomAccessIterator start, RandomAccessIterator end,                 T *){pop__heap(start, end, less<T>());}template <typename RandomAccessIterator>void pop__heap(RandomAccessIterator start, RandomAccessIterator end){__pop__heap(start, end, &*start);}template <typename RandomAccessIterator, typename CompareFunc>void sort__heap(RandomAccessIterator start, RandomAccessIterator end,                CompareFunc comp){while (end - start > 1){__pop__heap(start, end, &*start, comp);--end;}}template <typename RandomAccessIterator, typename T>void __sort__heap(RandomAccessIterator start, RandomAccessIterator end,                  T *){sort__heap(start, end, less<T>());}template <typename RandomAccessIterator>void sort__heap(RandomAccessIterator start, RandomAccessIterator end){__sort__heap(start, end, &*start);}template <typename RandomAccessIterator, typename CompareFunc>void make__heap(RandomAccessIterator start, RandomAccessIterator end,                CompareFunc comp){if (end - start <= 1){return;}unsigned int parent = (end - start - 2) / 2;while (parent > 0){__adjust__heap(start, end, parent, &*start, comp);--parent;}    __adjust__heap(start, end, 0, &*start, comp);}template <typename RandomAccessIterator, typename T>void __make__heap(RandomAccessIterator start, RandomAccessIterator end,                  T *){    make__heap(start, end, less<T>());}template <typename RandomAccessIterator>void make__heap(RandomAccessIterator start, RandomAccessIterator end){    __make__heap(start, end, &*start);}

测试代码:

template <typename CompareFunc>void test(const char * msg, CompareFunc comp){    /* Test Heap with comp */    cout << endl << msg << endl;    cout << "******* ====> *******" << endl;// test with vector{int ia[9] = { 0, 1, 2, 3, 4, 8, 9, 3, 5 };vector<int> ivec(ia, ia + 9);make__heap(ivec.begin(), ivec.end(), comp);for (int i = 0; i < ivec.size(); ++i){cout << ivec[i] << ' ';}cout << endl;ivec.push_back(7);push__heap(ivec.begin(), ivec.end(), comp);for (int i = 0; i < ivec.size(); ++i){cout << ivec[i] << ' ';}cout << endl;pop__heap(ivec.begin(), ivec.end(), comp);cout << ivec.back() << endl;ivec.pop_back();for (int i = 0; i < ivec.size(); ++i){cout << ivec[i] << ' ';}cout << endl;sort__heap(ivec.begin(), ivec.end(), comp);for (int i = 0; i < ivec.size(); ++i){cout << ivec[i] << ' ';}cout << endl;}// test with array 1{int ia[9] = { 0, 1, 2, 3, 4, 8, 9, 3, 5 };make__heap(ia, ia + 9, comp);sort__heap(ia, ia + 9, comp);for (int i = 0; i < 9; ++i){cout << ia[i] << ' ';}cout << endl;make__heap(ia, ia + 9, comp);for (int i = 0; i < 9; ++i){cout << ia[i] << ' ';}cout << endl;sort__heap(ia, ia + 9, comp);for (int i = 0; i < 9; ++i){cout << ia[i] << ' ';}cout << endl;pop__heap(ia, ia + 9, comp);cout << ia[8] << endl;}// test with array 2{int ia[6] = { 4, 1, 7, 6, 2, 5 };make__heap(ia, ia + 6, comp);for (int i = 0; i < 6; ++i){cout << ia[i] << ' ';}cout << endl;}cout << "******* <==== *******" << endl;}void test(const char * msg){    /* Test Heap with default comp: less<T>() */    cout << endl << msg << endl;    cout << "******* ====> *******" << endl;// test with vector{int ia[9] = { 0, 1, 2, 3, 4, 8, 9, 3, 5 };vector<int> ivec(ia, ia + 9);make__heap(ivec.begin(), ivec.end());for (int i = 0; i < ivec.size(); ++i){cout << ivec[i] << ' ';}cout << endl;ivec.push_back(7);push__heap(ivec.begin(), ivec.end());for (int i = 0; i < ivec.size(); ++i){cout << ivec[i] << ' ';}cout << endl;pop__heap(ivec.begin(), ivec.end());cout << ivec.back() << endl;ivec.pop_back();for (int i = 0; i < ivec.size(); ++i){cout << ivec[i] << ' ';}cout << endl;sort__heap(ivec.begin(), ivec.end());for (int i = 0; i < ivec.size( ); ++i){cout << ivec[i] << ' ';}cout << endl;}// test with array 1{int ia[9] = { 0, 1, 2, 3, 4, 8, 9, 3, 5 };make__heap(ia, ia + 9);sort__heap(ia, ia + 9);for (int i = 0; i < 9; ++i){cout << ia[i] << ' ';}cout << endl;make__heap(ia, ia + 9);for (int i = 0; i < 9; ++i){cout << ia[i] << ' ';}cout << endl;sort__heap(ia, ia + 9);for (int i = 0; i < 9; ++i){cout << ia[i] << ' ';}cout << endl;pop__heap(ia, ia + 9);cout << ia[8] << endl;}// test with array 2{int ia[6] = { 4, 1, 7, 6, 2, 5 };make__heap(ia, ia + 6);for (int i = 0; i < 6; ++i){cout << ia[i] << ' ';}cout << endl;}cout << "******* <==== *******" << endl;}bool MyLessFunc(int first, int second){    return (first < second);}struct MyLessFunctor{    bool operator() (int first, int second) const    {        return (first < second);    }};int main(){    test("test with default compare-function");    test("test with less<int>()", less<int>());    test("test with greater<int>()", greater<int>());    test("test with MyLessFunc-function", MyLessFunc);    test("test with MyLessFunctor()", MyLessFunctor());return 0;}