堆

#pragma once#include <vector>#include <assert.h>using namespace std;template<class T, class Compare = less<T> >class Heap{public:Heap(){}Heap(const T* array, size_t size){assert(array);for (int i = 0; i< size; ++i){_vec.push_back(array[i]);}for (int i = _vec.size()/2 - 1; i >=0; --i){_AdjustDown(_vec, i, _vec.size());}}Heap(const vector<T>& vec){_vec.swap(vec);for (int i = _vec.size()/2 - 1; i >=0; --i){_AdjustDown(_vec, i, _vec.size());}}// 插入一个数据x到最小堆中void Push(const T& x){_vec.push_back(x);if (_vec.size() > 1){_AdjustUp(_vec, _vec.size() - 1);}}// 删除堆顶元素void Pop(){int size = _vec.size();assert(size > 0);swap(_vec[0], _vec[size - 1]);_vec.pop_back();if (_vec.size() > 1){_AdjustDown(_vec, 0, _vec.size());}}const T& Top(){return _vec[0];}// 将根节点向下调整（小堆举例）void _AdjustDown(vector<T>& vec, int root, int size){// 1.child指向左孩子节点int child = root * 2 + 1;while (child < size){// 2.child指向左右孩子中小的节点if (child + 1 < size && Compare()(vec[child + 1], vec[child])){++child;}// 3.若child小于根节点，则交换child和root节点，并继续向下调整if (Compare()(vec[child], vec[root]))//if (vec[child] < vec[root]){swap(vec[child], vec[root]);root = child;child = root*2 + 1;}else{break;}}}// 一个节点向上调整（小堆举例说明）void _AdjustUp(vector<T>& vec, int pos){// 1.parent指向父节点int child = pos;int parent = (child - 1) / 2;// 当child==0时，则上调完成。不能使用parent来判断，parent不会小于0//while(parent >= 0)while(child > 0){// 2.若child小于父节点，则交换父子节点，并继续向上调整，直到根节点if (Compare()(vec[child], vec[parent]))//if (vec[child] < vec[parent]){swap(vec[child], vec[parent]);child = parent;parent = (child - 1) / 2;}else{break;}}}// 判断是否为空bool Empty(){return _vec.empty();}size_t Size(){return _vec.size();}private:vector<T> _vec;};// 测试堆void TestHeap(){Heap<int, greater<int>> heap;heap.Push(3);heap.Push(5);heap.Push(1);heap.Push(4);heap.Push(5);heap.Push(1);heap.Push(8);while (!heap.Empty()){cout<<heap.Top()<<" ";heap.Pop();}cout<<endl;//int array[10] = {9,1,3,5,6,7,8,0,2,4};int array[10] = {10,16,18,12,11,13,15,17,14,19};Heap<int> heap1(array, 10);while (!heap1.Empty()){cout<<heap1.Top()<<" ";heap1.Pop();}cout<<endl;}