堆排序 C++

#include <iostream>
using namespace std;

void AdjustHeap(int A[], int hlen, int i){
	int left = 2*(i+1)-1;
	int right = 2*(i+1);
	int largest = i;
	int temp;
	while(left < hlen || right < hlen){
		if(left < hlen && A[largest] < A[left])
			largest = left;
		if(right < hlen && A[largest] < A[right])
			largest = right;

		if( i != largest) //如果最大值不是父節點
		{
			temp = A[largest];
			A[largest] = A[i];
			A[i] = temp;

			i = largest; //新的父節點，已備疊代調堆
			left = 2*(i+1)-1;
			right = 2*(i+1);
		}else
			break; //不必調整
	}

}

void BuildHeap(int A[], int hlen){
	int i;
	int begin = hlen/2 -1;
	for(i=begin; i>=0; i--)
		AdjustHeap(A, hlen, i);
}

void HeapSort(int A[], int alen){
	int hlen = alen;
	int temp;
	BuildHeap(A, hlen);

	while(hlen > 1){
		temp = A[hlen -1];  //交換堆的第一個元素和堆的最後一個元素
		A[hlen - 1] = A[0];
		A[0] = temp;
		hlen--;  //堆的大小減一
		AdjustHeap(A, hlen, 0); //調堆
	}
}

int main() {

	int arr[5] = {6,2,4,1,5};
	HeapSort(arr,5);

	for(int i=0; i<5; i++)
		cout << arr[i] << " ";
	return 0;
}