堆排序

http://www.cnblogs.com/dolphin0520/archive/2011/10/06/2199741.html

//HeapSort by rtt 2014/7/12 
//array index from 0
void AjustHeap(int *a, int size, int i)
{
	int lchild = i*2 + 1;
	int rchild = i*2 + 2;
	int max = i;

	if (i > size/2 - 1)
		return;

	if (lchild <= size-1 && a[lchild] > a[max])
		max = lchild;
	if (rchild <= size-1 && a[rchild] > a[max])
		max = rchild;
	if (max != i)
	{
		swap(a[max], a[i]);

		for(i=0;i<size;i++)
			cout<<a[i]<<"";
		cout<<endl;

		AjustHeap(a, size, max);
	}
}

void BuildHeap(int *a, int size)
{
	if (a == NULL || size <=0)
		return;

	for (int i=size/2 - 1; i>=0; i--)
	{
		AjustHeap(a, size, i);
	}

}

void HeapSort(int *a, int size)
{
	if (a == NULL || size <=0)
		return;

	BuildHeap(a, size);

	for (int i=size - 1; i >= 0; --i)
	{
		swap(a[0], a[i]);
		AjustHeap(a, i, 0);
	}
}