int partition (int A[], int p, int r)
{
	int x = A[p];
	int i = p-1;
	int j = r+1;
	int temp;
	while (1)
	{
		while (A[--j] > x);
		while (A[++i] < x);
		if ( i<j )
		{
			temp=A[i];
			A[i]=A[j];
			A[j]=temp;
		}
		else
			return j;
	}
}

void quicksort(int A[], int p, int r)
{
	int q;
	if (p < r)
	{
		q=partition(A, p, r);
		quicksort(A, p, q);
		quicksort(A, q+1, r);
	}
}