堆排序

#include<stdio.h>
#include<stdlib.h>
# define LeftChild(i) (2*(i)+1)
void BuildDown(int a[],int n,int rootIndex)
{
int root=a[rootIndex];
int childIndex=LeftChild(rootIndex);
while(childIndex<n)
{
if(childIndex!=n-1&&a[childIndex+1]>a[childIndex])
childIndex++;
if(root<a[childIndex])
{
a[rootIndex]=a[childIndex];
rootIndex=childIndex;
childIndex=LeftChild(rootIndex);
}
else
break;
}
a[rootIndex]=root;
}
void HeapSort(int a[],int n)
{
int temp;
for(int rootIndex=(n-2)/2;rootIndex>=0;rootIndex--)
BuildDown(a,n,rootIndex);
for(int i=n-1;i>=0;i--)
{
temp=a[0];
a[0]=a[i];
a[i]=temp;
BuildDown(a,i,0);
}
}
int main()
{
int i, n, a[100];
printf("请输入需要排序元素的个数：");
scanf("%d", &n);
printf("随机生成的数组为：");
for (i = 0; i < n; i++)
{
a[i] = rand() % 100 + 1;
printf("%d ", a[i]);
}
a[i] = '';
printf(" ");
HeapSort(a,n);
printf(" 堆排序结果为(由小到大)：");
for (i = 0; i < n; i++)
printf("%d ", a[i]);
}