EIGHT PUZZLE PROGRAM IN JAVA.

 

8 PUZZLE PROGRAM.
The Eight-Puzzle program basically a 3x3 matrices.in that Three row was given and Three column.
The Task was is to Rearrange the row and column in a series wise..so as you can see in the start state the matrix Puzzle number was given Randomly.so The Task of goal state is to Rearrange in the sequence of 1,2,3,4.....9..for that purpose you can see a sample code of 8 Puzzle written in java.


CODE:-

class Node
{
    Node children[]=null;
    Node parent=null;
    int puzzle[][]=null;
    
    Node(int p[][],Node pa)
    {
        puzzle=p;
        parent=pa;
    }
    
    public void print()
    {
        System.out.println("**********");
        for (int i=0;i<puzzle.length;i++)
        {
            for (int j=0;j<puzzle.length;j++)
            {
                System.out.print(puzzle[i][j]);
                
            }
            System.out.println("");
        }
        System.out.println("**********");
    }
    
    public void printChildren()
    {
        for (int i=0;i<4;i++)
    {
        if(children[i]!=null)
        {
            (children[i]).print();
        }
    }
    }
    
    public void expand()
    {
        children=new Node[4];
        children[0]=expandDown();
        children[1]=expandUp();
        children[2]=expandLeft();
        children[3]=expandRight();
    }
    
    public Node expandDown()
    {
        Node n=new Node(puzzle.clone(),this);
        int zeroXY[]=n.getZero();
        if(zeroXY[1]-1>0 && zeroXY[1]-1<puzzle.length)
        {
            int temp=n.puzzle[zeroXY[0]][zeroXY[1]];
            n.puzzle[zeroXY[0]][zeroXY[1]]=n.puzzle[zeroXY[0]][zeroXY[1]-1];
            n.puzzle[zeroXY[0]][zeroXY[1]-1]=temp;
            n.print();
            return n;
        }
        else
        {
            return null;
        }
        
        
    }
    
    public Node expandUp()
    {
        Node n=new Node(puzzle.clone(),this);
        int zeroXY[]=n.getZero();      
        if(zeroXY[1]+1>0 && zeroXY[1]+1<puzzle.length)
        {
            int temp=n.puzzle[zeroXY[0]][zeroXY[1]];
            n.puzzle[zeroXY[0]][zeroXY[1]]=n.puzzle[zeroXY[0]][zeroXY[1]+1];
            n.puzzle[zeroXY[0]][zeroXY[1]+1]=temp;
            n.print();
            return n;
        }
        else
        {
            return null;
        }
        
        
    }
    
    public Node expandRight()
    {
        Node n=new Node(puzzle.clone(),this);
        int zeroXY[]=n.getZero();
        if(zeroXY[0]+1>0 && zeroXY[0]+1<puzzle.length)
        {
            int temp=n.puzzle[zeroXY[0]][zeroXY[1]];
            n.puzzle[zeroXY[0]][zeroXY[1]]=n.puzzle[zeroXY[0]+1][zeroXY[1]];
            n.puzzle[zeroXY[0]+1][zeroXY[1]]=temp;
            n.print();
            return n;
        }
        else
        {
            return null;
        }
        
    }
    
    public Node expandLeft()
    {
        Node n=new Node(puzzle.clone(),this);
        int zeroXY []=n.getZero();
        if(zeroXY[0]-1>0 && zeroXY[0]-1<puzzle.length)
        {
            int temp=n.puzzle[zeroXY[0]][zeroXY[1]];
            n.puzzle[zeroXY[0]][zeroXY[1]]=n.puzzle[zeroXY[0]-1][zeroXY[1]];
            n.puzzle[zeroXY[0]-1][zeroXY[1]]=temp;
            n.print();
            return n;
        }
        else
        {
            return null;
        }
        
    }
    
    
    
    int[] getZero()
    {
        int[] n=new int[2];
        for (int i=0;i<puzzle.length;i++)
        {
            for (int j=0;j<puzzle.length;j++)
            {
                if(puzzle[i][j]==0)
                {
                    n[0]=i;
                    n[1]=j;
                    //System.out.println(n[0]+","+n[1]);
                    return n;
                }
            }          
        }
        return null;
    }
}
class Puzzle8
{
    final static int GOAL [][]={{1,2,3},{4,5,6},{7,8,0}};  
    public static void main(String args[])
    {
        int board[][]={{1,2,3},{4,5,6},{7,8,0}};   
    Node Start=new Node(board,null);
    Start.expand();
    Start.printChildren(); 
    }
}