private static void Adjust (int[] list, int i, int m)
{
    int Temp = list[i];
    int j = i * 2 + 1;
  
    while (j <= m)
    {
        //more children
        if(j < m)
            if(list[j] < list[j + 1])
                j = j + 1;
  
        //compare roots and the older children
        if(Temp < list[j])
        {
            list[i] = list[j];
            i = j;
            j = 2 * i + 1;
        }
        else
        {
            j = m + 1;
        }
    }
  
    list [i] = Temp;
}
public static void HeapSort (int[] list)
{
    //build the initial heap
    for (int i = (list.Length - 1) / 2; i > = 0; i-)
        Adjust (list, i, list.Length - 1);
  
    //swap root node and the last heap node
    for (int i = list.Length - 1; i > = 1; i-)
    {
        int Temp = list [0];
        list [0] = list [i];
        list [i] = Temp;
        Adjust (list, 0, i - 1);
    }
}