DSA-Practice/NKnight.java at main · ysumitsingh159/DSA-Practice · GitHub

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package com.dsa;

public class NKnight {
    public static void main(String[] args) {
        int n=4;
        boolean[][] board = new boolean[n][n];
        knight(board,0,0,4);
    }
    static void knight(boolean[][]board,int row,int col,int knights)
    {
        if(knights==0)
        {
            display(board);
            System.out.println();
            return;
        }
        if(row==board.length-1 && col==board.length)
        {
            return;
        }
        if(col==board.length)
        {
            knight(board,row+1,0,knights);
            return;
        }
        if(isSafe(board,row,col))
        {
            board[row][col]=true;
            knight(board,row,col+1,knights-1);
            board[row][col]=false;
        }
        knight(board,row,col+1,knights);
    }
    static boolean isSafe(boolean[][] board,int row, int col)
    {
        if(isValid(board,row-2,col+1))
        {
            if(board[row-2][col+1])
            {
                return false;
            }
        }
        if(isValid(board,row-2,col-1))
        {
            if(board[row-2][col-1])
            {
                return false;
            }
        }
        if(isValid(board,row-1,col+2))
        {
            if(board[row-1][col+2])
            {
                return false;
            }
        }
        if(isValid(board,row-1,col-2))
        {
            if(board[row-1][col-2])
            {
                return false;
            }
        }
        return true;
    }
    static boolean isValid(boolean[][] board,int row, int col)
    {
        if(row>=0 && row<board.length  && col>=0 && col<board.length)
        {
            return true;
        }
        return false;
    }
    static void display(boolean[][] board)
    {
        for(boolean[] row : board)
        {
            for (boolean element : row)
            {
                if(element)
                {
                    System.out.print("K ");
                }
                else{
                    System.out.print("X ");
                }
            }
            System.out.println();
        }
    }
}