Program that shows the steps to solve a problem of Tower of Hanoi.

Hanoi.java

import java.util.*;

public class Hanoi{
    public static void towerOfHanoi(int numberOfRings){
        //final int NUM_OF_PEGS=3;
        List<Deque<Integer>> pegs = new ArrayList<>();
        for(int i=0; i<NUM_OF_PEGS; i++){
            pegs.add(new LinkedList());
        }
        //Initialize the first Peg
        for(int i=numberOfRings; i>=1; i--){
            pegs.get(0).addFirst(i);
        }
        hanoiHelper(numberOfRings, pegs, 0, 2, 1);
    }

    public static void hanoiHelper(int numOfRings, List<Deque<Integer>> pegs, int source, int dest, int intermed){
        if(numOfRings>0){
            hanoiHelper(numOfRings-1, pegs, source, intermed, dest);
            pegs.get(dest).addFirst(pegs.get(source).removeFirst());
            System.out.println("Move from PEG#"+source+" Dest #"+dest);
            hanoiHelper(numOfRings-1,pegs, intermed, dest, source);
        }
    }
    
    public static void main(String[] args){
        int numOfRings=4;
        towerOfHanoi(numOfRings);
    }
}