目录

仿函数

模拟实现

结果

大根堆

小根堆

完整代码

priority_queue.h

test.c

---

仿函数

仿函数的通俗定义：仿函数（functor）又称为函数对象（function object）是一个能行使函数功能

的类。仿函数的语法几乎和我们普通的函数调用一样，不过作为仿函数的类，都必须重operator()

运算符

模拟实现

结果

大根堆

小根堆

完整代码

priority_queue.h

#pragma oncetemplate<class T,class Contianer=vector<T>,class Compare=Less<T>>
class priority_queue
{
public:priority_queue(){ }void adjust_up(int child){int parent = (child - 1) / 2;while (child > 0){if (com(_con[parent], _con[child])){swap(_con[parent], _con[child]);child = parent;parent = (child - 1) / 2;}else{break;}}}void adjust_down(int parent){int child = parent * 2 + 1;while (child < _con.size()){if (child + 1 < _con.size() && com(_con[child], _con[child + 1])){++child;}if (com(_con[parent], _con[child])){swap(_con[parent], _con[child]);parent = child;child = parent * 2 + 1;}else{break;}}}template <class InputIterator>priority_queue(InputIterator first, InputIterator last):_con(first, last){for (int i = (_con.size() - 2) / 2; i >= 0; i--){adjustup(i);}}bool empty() const{return _con.empty();}size_t size() const{return _con.size();}const T& top(){return _con[0];}void push(const T& x){_con.push_back(x);adjust_up(_con.size() - 1);}void pop(){swap(_con[0], _con[_con.size() - 1]);_con.pop_back();adjust_down(0);}
private:Contianer _con;Compare com;
};

test.c

#define _CRT_SECURE_NO_WARNINGS 1#include <iostream>
#include <vector>using namespace std;#include "priority_queue.h"template<class T>
class Less
{
public:bool operator()(const T& x, const T& y){return x < y;}
};template<class T>
class Greater
{
public:bool operator()(const T& x, const T& y){return x > y;}
};void test()
{priority_queue<int> q;q.push(1);q.push(2);q.push(3);q.push(4);q.push(5);while (!q.empty()){cout << q.top() << ' ';q.pop();}cout << endl;
}int main()
{test();return 0;
}