First on the code
#include <stdio.h>
#include <stdlib.h>
void printf_array(int a[], int length)
{
int i = 0;
printf("array element:\n");
for (i = 0; i < length; i++) {
printf("%d\t",a[i]);
}
printf("\n");
}
void perDown(int a[], int parent, int length)
{
int temp = a[parent];
int child = 2 * parent + 1;
while (child < length) {
if(child + 1 < length && a[child+1] > a[child]) {//获取较大的儿子节点
child++;
}
if(a[child] > temp) {
a[parent] = a[child];
parent = child;
child = parent * 2 + 1;
} else {//跳出循环
//a[parent] = temp;//为什么放在这里不好使呢?
//怀疑编译器进行了内部优化导致此问题,放在这里和放在while体外,原则上是一样的意思
break;
}
}
a[parent] = temp;
printf_array(a, length);
}
//构建大根堆
void build_big_heap(int a[], int length)
{
int i = 0 ;
for (i = (length - 2) / 2; i >= 0; i--) {
perDown(a, i, length);
}
}
void heap_sort_increasing(int a[], int length)
{
int i = 0;
int temp = 0;
build_big_heap(a, length);
printf("=========================================\n");
//去掉堆头,重新排序
for (i = length - 1; i > 0; i--) {
temp = a[i];
a[i] = a[0];
a[0] = temp;
perDown(a, 0, i);
}
}
int main()
{
int array[] = {4,2,5,1,7,3};
printf_array(array, 6);
heap_sort_increasing(array, 6);
printf_array(array, 6);
return 0 ;
}