大小堆C++实现

C++大小堆实现（仿函数）

具体代码如下

#pragma once
#include<iostream>
#include<vector>

using namespace std;

template<class T>
class Big
{
public:
    bool operator()(T x, T y)
    {
        return x > y;
    }
};
template<class T=int>
class Sma
{
public:
    bool operator()(T x, T y)
    {
        return x < y;
    }
};

template<class T,class Cmp>
class Heap
{
public:
    Heap()
    {}
    Heap(const T* arr, size_t size)
    {
        for (int i = ; i < size; ++i)
        {
            _heap.push_back(arr[i]);
        }
        int root = (_heap.size() - ) / ;//找到第一个非叶子结点
        while (root>=)
            //向下调整
            AdjustDown(root--);
    }

    void Push(T & t)
    {
        _heap.push_back(t);
        AdjustUp(_heap.size() - );
    }
    void pop()
    {
        if (_heap.size() == )
            return;
        if (_heap.size() <= )
        {
            swap(_heap[], _heap[_heap.size() - ]);
            _heap.pop_back();
        }
        else
        {
            swap(_heap[], _heap[_heap.size() - ]);
            _heap.pop_back();
            AdjustDown();
        }
    }
    bool IsEmpty()const
    {
        return _heap.size() == ;
    }
    const T & top() const
    {
        if (_heap.size() != )
            return _heap[];
        else
            throw exception("this is a bug");
    }
protected:
    void AdjustDown(int root)
    {
        //int child = root * 2 + 2 >= _heap.size() ? root * 2 + 1 : Cmp(_heap[root * 2 + 1], _heap[root * 2 + 2]) ? root * 2 + 1 : root * 2 + 2;
        while (root <= (_heap.size() - ) / )
        {
            int child = root *  +  >= _heap.size() ? root *  +  : Cmp()(_heap[root *  + ], _heap[root *  + ]) ? root *  +  : root *  + ;
            if (!Cmp()(_heap[root], _heap[child]))
            {
                swap(_heap[root], _heap[child]);
            }
            else
            {
                break;
            }
            root = child;
        }
    }

    void AdjustUp(int child)
    {
        while (child >= )
        {
            int root = (child - ) / ;
            if (!Cmp()(_heap[root], _heap[child]))
            {
                swap(_heap[root], _heap[child]);
            }
            child = root;
        }
    }
protected:
    vector<T> _heap;
};

void test_heap()
{
    int arr[] = { , , , , , , , , ,  };
    Heap<int, Sma<int> >hp1(arr, );
    int b = ;
    hp1.Push(b);
    cout << "Over!" << endl;
    while (!hp1.IsEmpty())
    {
        cout << hp1.top() << " ";
        hp1.pop();
    }
    system("pause");
}