优先队列（堆）

来源：互联网发布：linux awk 编辑：程序博客网时间：2024/05/21 10:15

一个优先队列的实现：

#include <iostream>#define MAXSIZE 100typedef struct heap {    int size;    int capacity;       int* a;}Heap;Heap heap;void initHeap() {    heap.size = 0;    heap.capacity = MAXSIZE;    heap.a = new int[MAXSIZE];}void insert(int data) {   heap.size += 1;    heap.a[heap.size] = data;    int index = heap.size;    for(; index > 1; index = index / 2) {        if(heap.a[index] < heap.a[index/2]) {            int tmp = heap.a[index];            heap.a[index] = heap.a[index/2];            heap.a[index/2] = tmp;        }        else {            break;        }    }}int deleteMin() {    int min = heap.a[1];    int i = 1;    int index = 1;    int lastData = heap.a[heap.size];    while(true) {        if(i*2+1 <= heap.size) {            if(heap.a[i*2] < heap.a[i*2+1]) {                heap.a[i] = heap.a[i*2];                i = i*2;            }            else {                heap.a[i] = heap.a[i*2+1];                i = i*2+1;            }        }        else if(i*2 <= heap.size) {            heap.a[i] = heap.a[i*2];            i = i*2;        }        else {            break;        }    }    heap.a[i] = lastData;    heap.size -= 1;    return min;}void print() {    for(int i=1; i <= heap.size; i++) {        std::cout << heap.a[i] << ",";        std::cout << std::endl;    }}int main() {    initHeap();    insert(9);    insert(8);    insert(7);    insert(6);    insert(5);    insert(4);    //print();    deleteMin();    print();    return 0;}

堆是一棵被完全填满的二叉树（完全二叉树），它的任意节点小于它的子节点，它的插入，删除操作时间复杂度为O(log2N);

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