堆的实现及堆的各种应用

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#include<iostream>#include<vector>using namespace std;template<class T>class Less //仿函数{public:    Less()    {}    bool operator()(const T& l, const T& r)    {        return l < r;  //实现小堆    }};template<class T>class Greater{public:    Greater()    {}    bool operator()(const T& l, const T& r)    {        return l > r;  //实现大堆    }};template <class T, class compare = Less>class Heap{public:    Heap(T* array = NULL, size_t size = 0)    {        for (int i = 0; i < size; i++)        {            _arr.push_back(array[i]); //将数据存入顺序表中        }        int root = size / 2 - 1;        for (; root >= 0; root--)        {            _AdjustDown(root, _arr.size());        }    }    void push(const T& x) //插入一个叶子节点    {        _arr.push_back(x);        _AdjustUp();    }    void pop()  //删除堆的根节点    {        _arr[0] = _arr[_arr.size() - 1];  //将最后一个节点的值赋给第一个节点，相当于删除第一个节点        _arr.pop_back(); //删除最后一个节点        int root = _arr.size() / 2 - 1;  //重新排序        for (; root >= 0; root--)        {            _AdjustDown(root, _arr.size());        }    }    T& Top()    {        return _arr.front();    }    bool Empty()    {        return _arr.empty();    }    void HeapSort() //堆排序    {        for (int i = _arr.size(); i >= 1; i--)        {            swap(_arr[0], _arr[i - 1]);            int root = (i - 1) / 2 - 1;            for (; root >= 0; root--)            {                _AdjustDown(root,i - 1);            }         }    }    void Print()    {        for (int i = 0; i < _arr.size(); i++)        {            cout << _arr[i] << " ";        }        cout << endl;    }private:    void _AdjustDown(int root, int size)     {        int left = root * 2 + 1;        int right = left + 1;        int key = left;        while (left < size)        {            if (right < size) //防止越界            {                if (compare()(_arr[right], _arr[left]))                {                    key = right;                }            }            if (compare()(_arr[key], _arr[root]))            {                swap(_arr[key], _arr[root]);                //所有变量都要更新                root = key;                left = root * 2 + 1;                right = left + 1;                key = left; //重要            }            else            {                break;            }        }    }    void _AdjustUp()    {        int root = (_v.size() - 2) / 2;        int child = _v.size() - 1;        //while ((root >= 0) && (_v[root] < _v[child]))        // 当child==0时，则上调完成。不能使用parent来判断，parent不会小于0        while ((child > 0) && Com()(_v[child],_v[root]))        {            swap(_v[root], _v[child]);            child = root;            root = (child - 1) / 2;        }private:    vector<T> _arr;};template<class T>class PriorityQueue //优先级队列{public:    PriorityQueue()    {}    void push(const T& x)    {        hp.push(x);    }    void pop()    {        hp.pop();    }    T& top()    {        return hp.Top();    }    bool empty()    {        return hp.Empty();    }private:    Heap<T, Less<T>> hp;};//在30个无序的数中找到最大的前十个void TestFindMax(){    int arr[30] = { 10, 16, 18, 12, 11, 13, 15, 17, 14, 19 ,99,32,45,67,89,34,98,77,56                    ,54,12,78,6,5,2,90,65,23,100,97};    Heap<int, Less<int>> hp(arr, 10);    int size = sizeof(arr) / sizeof(arr[0]);    for (int i = 10; i < size; i++)    {        hp.pop(); //删掉最小的        hp.push(arr[i]);    }    hp.Print();}void TestHeap(){    int arr[10] = { 10, 16, 18, 12, 11, 13, 15, 17, 14, 19 };    Heap<int,Greater<int>> hp(arr, 10);    hp.push(20);    hp.pop();    hp.HeapSort();    hp.Print();}void TestPriorityQueue(){    PriorityQueue<int> pq;    pq.push(4);    pq.push(6);    pq.push(2);    pq.push(8);    cout << pq.top() <<" ";    pq.pop();    cout << pq.top() << " ";    pq.pop();    cout << pq.top() << " ";    pq.pop();    cout << pq.top() << " ";}int main(){    TestHeap();    //TestPriorityQueue();    //TestFindMax();    getchar();    return 0;}
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