堆排序 C++实现

#include<iostream>
#include<vector>
#include<stack>
#include<algorithm>
#include<string>
#include<set>
#include <functional>
using namespace std;
//构造最大堆
void MaxHeapFixDown(int a[], int i, int n)
{
	int j = 2 * i + 1;
	int temp = a[i];
	while (j<n) 
	{
		if (j + 1 < n&&a[j] < a[j + 1])
			++j;
		if (temp>a[j])
			break;
		else 
		{
			a[i] = a[j];
			i = j;
			j = 2 * i + 1;
		}
	}
	a[i] = temp;
}
//堆排序
void HeapSort(int a[], int n) {
	for (int i = n / 2 - 1; i >= 0; i--)
		MaxHeapFixDown(a, i, n);//n个元素，最后一个非叶结点下标：n/2-1
	for (int i = n - 1; i >= 1; i--) {
		swap(a[i], a[0]);
		MaxHeapFixDown(a, 0, i);
	}
}
int main()
{
	int a[10] = { 4,8,7,0,3,5,9,1,1,8 };
	HeapSort(a, 10);
	for (int i = 0; i < 10; i++)
		cout << a[i] << " ";
	cout << endl;
	return 0;
}