Problem solving exercise (challenging:)


Write a Java class GameOfFifteen that implements the game of 15:
https://en.wikipedia.org/wiki/15_puzzle

The class should contain:

- a public default constructor that creates a game configuration  with 15 
cells positioned randomly.

- a public method toString() that returns the string representation of
the actual configuration of the game. For example:

3  8  7  6
13  2 10   
15  1 12 11
14  9  4  5

- a method

  public void move(int x, int y)

that moves the cell at position (x,y). The coordinates range from 0 to 3,
for instance, the coodrinate of "13" is (1,0) and the coordinate of "11"
is (2,3). A cell can be moved if there is an empty cell on the same row or
on the same column. If a given cell can not be moved, the method should do
nothing. For example, if a user enters x=1 and y=2, the number at position (1,2),
that is 10, should move one position to the right. The resulting configuration of the 
game  is then:

3  8  7  6
13  2    10
15  1 12 11
14  9  4  5



You can use the following template:

import static dit948.SimpleIO.*;
import static dit948.Random.*;

public class GameOfFifteen {
	
		// 0 indicates empty cell
		private final int[][] frame = new int[4][4];

		public GameOfFifteen() {
			for (int num = 1; num <= 15; num++)
				randomMove(num);
		}

		private void randomMove(int num) {
			int x, y;
			do {
				x = randomInt(4);
				y = randomInt(4);
			}
			while (frame[x][y] != 0);
			
			frame[x][y] = num;
		}

		public String toString() {
			String result = "";
			for (int x = 0; x < 4; x++)
				result += String.format("%2d %2d %2d %2d\n",
						frame[x][0],
						frame[x][1],
						frame[x][2],
						frame[x][3]).replace(" 0", "  ");

			return result;
		}

		public void move(int x, int y) {
			tryLeft(x, y);
			tryRight(x, y);
			tryUp(x, y);
			tryDown(x, y);
		}

		private void tryLeft(int x, int y) {
			//code here
		}

		// same for tryRight, tryUp, tryDown methods

		public static void main(String[] args) {
			GameOfFifteen game = new GameOfFifteen();
			
			do {
				System.out.println(game);
				System.out.print("Enter x: ");
				int x = readInt();
				System.out.print("Enter y: ");
				int y = readInt();
				game.move(x, y);
			}
			while (true);
		}


	}