// else condition, 12-13, added in addition to original partition function.
size_t partition(int * arr, int l, int r) 
{
	int i = l + 1, j = r;
	int pivot = arr[l];	
	while (i <= j) 
	{
		while (pivot < arr[j])
			j--;
		if (j == l)
			return l;
		else
		{ }
		while (i < r && pivot > arr[i])
			i++;
		if (i == j) break;
		if (i < j)
			swap(&arr[i], &arr[j]);
	}
	swap(&arr[l], &arr[j]);	
	return j;
}