private static int Partition (int[] list, int i, int j)
{
    int Key = list [i];
  
    while (i < j)
    {
        //j to the left scan
        while (list [j] >= Key && i < j)
            j--;
  
        if(i< j)
            list [i++] = list [j];
  
        //i to the right scan
        while (list [i] <= Key && i < j)
            i++;
  
        IF (i < j)
            list [j--] = list[i];
    }
  
    list [i] = Key;
    return i;
}
public static void QuickSort (int[] list, int low, int high)
{
    if(low < high - 1)
    {
        int Key = Partition (list, low, high);
        QuickSort (list, low, Key - 1);
        QuickSort (list, Key + 1, high);
    }
}