// Purpose.  Domain layer to Towers of Hanoi - algorithmic solution

import java.util.List;
import java.util.ArrayList;

class LeafMove {
  public int from, to;
  public LeafMove( int f, int t ) { from = f;  to = t; }
}

class TowersOfHanoiAlgo {
  static void move( int n, int from, int to, int aux, List instructions ) {
    if (n == 1) {
      instructions.add( new LeafMove(from,to) );
      return;
    }
    move( n-1, from, aux, to, instructions );	
    instructions.add( new LeafMove(from,to) );
    move( n-1, aux, to, from, instructions );	
  }

  public static void main( String[] args ) {
    int size = 5;
    if (args.length > 0) size = Integer.parseInt( args[0] );

    List instructions = new ArrayList();
    move( size, 0, 2, 1, instructions );
    System.out.println( "disks is " + size + ", moves is " + instructions.size() );

    new TowersOfHanoiPresentation( size, instructions );
} }

// number of disks     number of moves
//        2                    3
//        3                    7
//        4                   15
//        5                   31
//        6                   63
//        7                  127