CareerCup_3.4 - HanoiTower

HanoiTower.java

package Chapter3;

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

public class HanoiTower {
    private List<Stack<Integer>> towers;

    public HanoiTower(int t, int d) {
	towers = new ArrayList<>();
	for (int i = 0; i < t; i++) {
	    towers.add(new Stack<Integer>());
	}
	for (int i = d; i > 0; i--) {
	    towers.get(0).push(i);
	}
    }

    // move the tower from start to end
    public void finishHanoi() {
	move(towers.get(0).size(), 0, towers.size() - 1);
    }

    // moving n disks from one tower to another
    private void move(int n, int from, int to) {
	if (n == 1) {
	    // base case - moving one disk
	    slide(from, to);
	    return;
	}
	int another = (from + to) == 1 ? 2 : ((from + to) == 2 ? 1 : 0);
	move(n - 1, from, another);
	slide(from, to);
	move(n - 1, another, to);
    }

    // sliding one disk from one tower to another
    private void slide(int from, int to) {
	if (towers.get(to).isEmpty()
		|| towers.get(from).peek() < towers.get(to).peek()) {
	    int diskSize = towers.get(from).pop();
	    towers.get(to).push(diskSize);
	    System.out.println("move disk " + diskSize + " from Tower "
		    + (from + 1) + " to Tower " + (to + 1));
	} else
	    System.out.println("moving large disk on top of small disk");
    }

    private void print() {
	int i = 1;
	for (Stack<Integer> t : towers) {
	    System.out.print("[Tower " + (i++) + "]: ");
	    t.print();
	    System.out.println();
	}
    }

    public static void main(String[] args) {
	HanoiTower tower = new HanoiTower(3, 5);
	System.out.println("----------------------------------------------");
	tower.print();
	System.out.println("----------------------------------------------");
	tower.finishHanoi();
	System.out.println("----------------------------------------------");
	tower.print();
	System.out.println("----------------------------------------------");
    }
}

Node.java

package Chapter3;

public class Node<T> {
    public T value;
    public Node<T> next;
    
    public Node(T d, Node<T> n){
   	value = d;
   	next = n;
    }
}

Stack.java

package Chapter3;

public class Stack<T> {
    private int size = 0;
    public Node<T> top = null;

    public int size() {
	return size;
    }

    public boolean isEmpty() {
	return size == 0;
    }

    public void push(T value) {
	Node<T> n = new Node<T>(value, top);
	size++;
	top = n;
    }

    public T pop() {
	if (top == null)
	    return null;
	T res = top.value;
	top = top.next;
	size--;
	return res;
    }

    public void print() {
	if(top == null) return;
	Node<T> cur = top;
	while(cur != null) {
	    System.out.print(cur.value + "; ");
	    cur = cur.next;
	}
	System.out.println();
    }

    public T peek() {
	if (top == null)
	    return null;
	return top.value;
    }
}