fork download
copy 
  1. /** finger exercise: Lucas' "Towers of Hanoi".
  2.  * Based on code presented at https://c...content-available-to-author-only...e.com/a/116290/93149 */
  3. class Ideone {
  4.  
  5.     static class LucasTower<E> extends java.util.ArrayDeque<E> {
  6. 		private static final long serialVersionUID = 3049952862056404246L; // YAGNI?
  7. 		private final String name;
  8.  
  9.         public LucasTower(String name) { this.name = name; }
  10.     // YAGNI   LucasTower(String n, int c) { super(c); name = n; }
  11.         void addEach(E ...n) { for (E e : n) { add(e); } }
  12.     /** Do as see fit with {@code count, mid, to} just before
  13.      *   the bottom disk of some invocation of {@code move} is moved. Old school override */
  14.         public void before(int count, LucasTower<E> mid, LucasTower<E> to) {
  15.             System.out.println(name + ": pushing " + peek() + " to " + to.name);
  16.         }
  17.     /** Do as see fit with {@code count, mid, to} just after
  18.      *   the bottom disk of some invocation of {@code move} is moved. Old school override */
  19.         public void after(int count, LucasTower<E> mid, LucasTower<E> to) {
  20.     //      System.out.println(name + ": pushed popped " + to.peek() + " to " + to.name);
  21.         }
  22.     /** move the top {@code count} discs to {@code to} */
  23.         public void move(int count, LucasTower<E> mid, LucasTower<E> to) {
  24.             if (0 < count) {
  25.                 move(count - 1, to, mid);
  26.                 before(count, mid, to);
  27.                 to.push(pop());
  28.                 after(count, mid, to);
  29.                 mid.move(count - 1, this, to);
  30.             }
  31.         }
  32.     }
  33.  
  34.     public static void main(String[] args) {
  35.         LucasTower<Number>
  36.         	from= new LucasTower<>("A"),
  37.         	mid = new LucasTower<>("B"),
  38.         	to  = new LucasTower<>("C");
  39.         from.addEach(10, 15, 20, 25);
  40.         from.move(from.size(), mid, to);
  41.     }
  42. }
Success #stdin #stdout 0.11s 320576KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
A: pushing 10 to B
A: pushing 15 to C
B: pushing 10 to C
A: pushing 20 to B
C: pushing 10 to A
C: pushing 15 to B
A: pushing 10 to B
A: pushing 25 to C
B: pushing 10 to C
B: pushing 15 to A
C: pushing 10 to A
B: pushing 20 to C
A: pushing 10 to B
A: pushing 15 to C
B: pushing 10 to C
https://ideone.com/YhJ9wQ
language:
Java (HotSpot 12)
created:
8 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!