/**
 * Solves the Tower of Hanoi problem.
 *
 * @author Sean Barker
 */
public class Hanoi {

  private static int numMoves = 0;

  // print a move of one disk from peg "start" to peg "finish"
  private static void moveDisk(String start, String finish) {
    numMoves++;
    System.out.println(numMoves + ". " + start + " -> " + finish);
  }

  // move an entire tower from one peg to another peg, using a third temporary peg
  public static void moveTower(int numDisks, String start, String finish, String temp) {
    if (numDisks == 1) {
      // base case
      moveDisk(start, finish);
    } else {
      // step 1: move n - 1 disks from start to temp
      moveTower(numDisks - 1, start, temp, finish);

      // step 2: move largest disk from start to finish
      moveDisk(start, finish);

      // step 3: move n - 1 disks from temp to finish
      moveTower(numDisks - 1, temp, finish, start);
    }
  }

  public static void main(String args[]) {
    int numDisks = 5;
    // three pegs are named "A", "B", and "C" (left, middle, right)
    // move left tower to right peg with middle peg as temp
    moveTower(numDisks, "A", "C", "B"); 
  }

}