using Nemerle.IO;

module Hanoi {
  mutable tops : array [array [int]];
  mutable numbers : array [int];
  mutable n : int;
  mutable move_no : int;

  show_top (k : int, n : int) : void
  {
    if (tops[k][n] == 0) printf (" | ")
    else printf ("(%d)", tops[k][n]);
    printf ("   ")
  }

  show_tops () : void
  {
    for (mutable i = n; i >= 1; i = i - 1) {
      show_top (1, i);
      show_top (2, i);
      show_top (3, i);
      printf ("\n")
    }
  }
  
  move (a : int, b : int) : void
  {
    printf ("%d -(%d)-> %d\n", a, move_no, b);
    tops[b][numbers[b]] = tops[a][numbers[a]-1];
    tops[a][numbers[a]-1] = 0;
    numbers[a] = numbers[a] - 1;
    numbers[b] = numbers[b] + 1;
    move_no = move_no + 1;
    show_tops ();
  }

  hanoi (n : int, a : int, b : int, c : int) : void
  {
    when (n > 0) {
      hanoi (n - 1, a, c, b);
      move (a, b);
      hanoi (n - 1, c, b, a);
    }
  }

  init () : void
  {
    printf ("the tower of hanoi (please type the size ?) ");
    scanf ("%d", n);
    
    numbers = array (n + 1);
    tops = array [null, array (n + 1), array (n + 1), array (n + 1)];
    for (mutable i = 1; i <= n; i = i + 1) {
      tops[1][n - i + 1] = i;
      tops[2][n - i + 1] = 0;
      tops[3][n - i + 1] = 0;
    };
    numbers[1] = n + 1;
    numbers[2] = 1;
    numbers[3] = 1;
    move_no = 1;
    show_tops ();
  }

  Main () : void
  {
    init ();
    hanoi (n, 1, 3, 2);  
  }
}