[算法]二叉堆

来源：互联网发布：百度算法调整2017 编辑：程序博客网时间：2024/05/15 11:52
#include <iostream>using namespace std;#define MAXSIZE 100class BinaryHeap {private:    int values[MAXSIZE];    int size{0};    bool cmp(int left, int right) {        return left < right;    }    int parentIndex(int index) {        return (index - 1) >> 1;    }    int leftSonIndex(int index) {        return ((index + 1) << 1) - 1;    }    int rightSonIndex(int index) {        return (index + 1) << 1;    }public:    BinaryHeap() {        memset(values, 0, sizeof(values));        size = 0;    }    void push(int key) {        int pivot;        size++;        for (pivot = size - 1; pivot > 0; pivot = (pivot - 1) >> 1) {            if (cmp(key, values[parentIndex(pivot)])) {                values[pivot] = values[parentIndex(pivot)];            } else {                break;            }        }        values[pivot] = key;    }    bool empty() {        return size == 0;    }    int top() {        if (!empty()) {            return values[0];        }        return -1;    }    void pop() {        if (!empty()) {            int pivot, tmp;            size--;            for (pivot = 0; leftSonIndex(pivot) < size; ) {                tmp = (rightSonIndex(pivot) <= size &&                        cmp(values[rightSonIndex(pivot)],                            values[leftSonIndex(pivot)])                      ) ? rightSonIndex(pivot) : leftSonIndex(pivot);                if (cmp(values[tmp], values[size])) {                    values[pivot] = values[tmp];                    pivot = tmp;                } else {                    break;                }            }            values[pivot] = values[size];        }    }};int main() {    BinaryHeap heap;    int size = 10;    for (int i = 0; i < size; ++i) {        heap.push(i);    }    for (int j = 0; j < size; ++j) {        cout << heap.top();        heap.pop();    }    return 0;}
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