堆的基本操作：定义、创建、插入、删除、排序

#include <iostream>using namespace std;#include <cstdlib> #include <cstring> typedef int heap_elem_t; typedef struct heap_t {    int size;   /** 实际元素个数*/    int capacity;   /** 容量，以元素为单位*/    heap_elem_t *elems;     /** 堆的数组*/    int (*cmp)(const heap_elem_t*, const heap_elem_t*);     /** 元素的比较函数*/}heap_t;int cmp_int(const int *x, const int *y) {    const int sub = *x - *y;    if(sub > 0)         return 1;    else if(sub < 0)         return -1;    else         return 0; }heap_t* heap_create(const int capacity, int (*cmp)(const heap_elem_t*, const heap_elem_t*)) {    heap_t *h = (heap_t*)malloc(sizeof(heap_t));    h->size = 0;    h->capacity = capacity;    h->elems = (heap_elem_t*)malloc(capacity * sizeof(heap_elem_t));    h->cmp = cmp;    return h;}void heap_destroy(heap_t *h) {    free(h->elems);    free(h);}int heap_empty(const heap_t *h) {    return h->size == 0;}int heap_size(const heap_t *h){    return h->size;}void heap_sift_down(const heap_t *h, const int start) {    int i = start;    int j;    const heap_elem_t tmp = h->elems[start];    for(j = 2 * i + 1; j < h->size; j = 2 * j + 1)     {        if(j < (h->size - 1) && h->cmp(&(h->elems[j]), &(h->elems[j + 1])) > 0)         {            j++;    /* j 指向两子女中小者*/        }        if(h->cmp(&tmp, &(h->elems[j])) <= 0)         {            break;        }         else         {            h->elems[i] = h->elems[j];            i = j;        }    }    h->elems[i] = tmp;}void heap_sift_up(const heap_t *h, const int start) {    int j = start;    int i= (j - 1) / 2;    const heap_elem_t tmp = h->elems[start];    while(j > 0)     {        if(h->cmp(&(h->elems[i]), &tmp) <= 0)         {            break;        }         else         {            h->elems[j] = h->elems[i];            j = i;            i = (i - 1) / 2;        }    }    h->elems[j] = tmp;}void heap_push(heap_t *h, const heap_elem_t x) {    if(h->size == h->capacity)  /* 已满，重新分配内存*/    {           heap_elem_t* tmp = (heap_elem_t*)realloc(h->elems, h->capacity * 2 * sizeof(heap_elem_t));        h->elems = tmp;        h->capacity *= 2;    }    h->elems[h->size] = x;    h->size++;    heap_sift_up(h, h->size - 1);}void heap_pop(heap_t *h) {    h->elems[0] = h->elems[h->size - 1];    h->size --;    heap_sift_down(h, 0);}heap_elem_t heap_top(const heap_t *h) {    return h->elems[0];}<pre name="code" class="cpp">void heap_sort(heap_elem_t *a, const int n, int (*cmp)(const heap_elem_t*, const heap_elem_t*)) {        int i;        heap_t *h;        heap_elem_t tmp;        h = heap_create(n, cmp);        h->elems = a;        i = (h->size - 2)/2;    /* 找最初调整位置：最后分支结点*/        while (i >= 0)   /* 自底向上逐步扩大形成堆*/        {               heap_sift_down(h, i);            i--;        }        for (i = h->size - 1; i > 0; i--)         {            tmp = h->elems[i];            h->elems[i] = h->elems[0];            h->elems[0] = tmp;            h->size = i;    /* 相当于h.size -- */            heap_sift_down(h, 0);        }        heap_destroy(h);}