堆排序（C++版）

#include <iostream>

using namespace std;

void HeapAdjust(int* a, int start, int n)
{
int max=start;
int lchild = start*2+1;
int rchild = start*2+2;
if(start <= (n-1)/2){
if(lchild <=n && a[lchild]>a[max]){
max = lchild;
}
if(rchild <=n && a[rchild]>a[max]){
max = rchild;
}
if(max!=start){
swap(a[start], a[max]);
HeapAdjust(a, max, n);
}
}
}

void BuildHeap(int* a, int n){  //n: [0,n]
for(int i = (n-1)/2; i >=0;i--){
HeapAdjust(a, i, n);
}
}

void HeapSort(int *a,int n)
{
BuildHeap(a,n);
for(int i=n;i>=1;i--)
{
swap(a[0],a[i]);
HeapAdjust(a,0,i-1);
}
}

int main(int argc, char *argv[])
{
int a[]={6,36,77,31,181,7,8};
BuildHeap(a,6);
for(int i=0;i<7;i++){
cout << a[i] <<endl;
}
cout << "=================" <<endl;
HeapSort(a,6);
for(int i=0;i<7;i++){
cout << a[i] <<endl;
}
return 0;
}