HeapSort(int data[ ], int n) 
{register int i;

 /* create a heap */

 for (i = n/2 - 1; i >= 0; --i)
   /* LI: The nodes i+1,...,n/2-1 satisfy the heap property. */ 
   move_down (data,i,n-1);

  /* move the root item to the end of the array data 
     and restore the heap property to the tree 
     data[0],...,data[i-2] by selecting the
     largest item */

 for (i = n-1; i > 1; --i) { 
   /* LI: The largest n-i-1 elements are in
      their proper places.  
      data[0],...,data[i] is a heap containing the
      other elements. */ 
   swap (data, data+i);
   move_down(data,0,i-1);
 }
 if (data[0] > data[1])
   swap (data, data+1);
}