快速排序

int (int* data, int length, int start, int end)
{
	if (data == nullptr || length <= 0 || start < 0 || end >= length)
		return -1;

	int small = start - 1;
	for (int index = start; index < end; index++)
	{
		if (data[index] < data[end])
		{
			small++;
			if (small != index)
				swap(data[index], data[small]);
		}
	}
	small++;
	swap(data[small], data[end]);
	return small;
}
void Qsort(int* data, int length, int start, int end)
{
	if (start == end)
		return;
	int index = Partition(data, length, start, end);
	if (index > start)
		Qsort(data, length, start, index - 1);
	if (index < end)
		Qsort(data, length, index + 1, end);
}

int myPartition(int* data, int length, int start, int end)
{
	int left = start, right = end - 1;
	while (left < right)
	{
		while (data[left] < data[end] && left < right)
			left++;
		while (data[right] >= data[end] && left < right)
			right--;
		swap(data[left], data[right]);
	}
	if (data[left] >= data[end])
		swap(data[left], data[end]);
	else
		swap(data[++left], data[end]);
	return left;
}
void myQsort(int* data, int length, int start, int end)
{
	if (data == nullptr || length <= 0 || start >= end)
		return;
	int index = myPartition(data, length, start, end);
	myQsort(data, length, start, index - 1);
	myQsort(data, length, index + 1, end);
}