堆排序---C语言

堆排序详解：点这里。

使用向下调整算法实现堆排序，完整代码

#include<stdio.h>

void Swap(int* p1, int* p2)
{
	int* tmp = *p1;
	*p1 = *p2;
	*p2 = tmp;
}

void Print(int* arr, int n)
{
	for (int i = 0; i < n; i++)
	{
		printf("%d ", arr[i]);
	}
	printf("\n");
}

// 堆排序，建大堆
void AdjustDown(int* a, int n, int parent)
{
	int child = 2 * parent + 1;
	while (child < n)
	{
		if (child + 1 < n && a[child + 1] > a[child])
		{
			child++;
		}
		if (a[parent] < a[child])
		{
			Swap(&a[parent], &a[child]);
			parent = child;
			child = 2 * parent + 1;
		}
		else
		{
			break;
		}
	}
}

void HeapSort(int* a, int n)
{
	//排升序，建大堆
	for (int i = (n - 1 - 1) / 2; i >= 0; i--)
	{
		AdjustDown(a, n, i);
	}
	int end = n - 1;
	while (end > 0)
	{
		Swap(&a[0], &a[end]);
		AdjustDown(a, end, 0);
		end--;
	}
}

void test()
{
	int arr[] = { 6,3,4,2,0,1,8,7,5 };
	int len = sizeof(arr) / sizeof(int);
	HeapSort(arr, len);
	Print(arr, len);
}

int main()
{
	test();
	return 0;
}