public class Main3
{
    public static void nQueens( char[][] board,int row){
        if(row== board.length) {
            printBoard(board);
            return;
        }
        for (int j = 0; j < board.length; j++) {
           if(isSafe(board,row,j)){
               board[row][j]='Q';
               nQueens(board,row+1);
               board[row][j]='X';
           }
        }
    }
    public static void printBoard(char[][] board){
        System.out.println("---------chess board---------");
        for (char[] chars : board) {
            for (int j = 0; j < board.length; j++) {
                System.out.print(chars[j] + " ");
            }
            System.out.println();
        }
    }
    public static boolean isSafe(char[][] board,int row,int col){
        for(int i=row-1;i>=0;i--){
            if(board[i][col]=='Q') return false;
        }
        for(int i=row-1,j=col+1;i>=0&&j< board.length;i--,j++){
            if(board[i][j]=='Q') return false;
        }
        for(int i=row-1,j=col-1;i>=0&&j>=0;i--,j--){
            if(board[i][j]=='Q') return false;
        }
        return true;
    }
    public static void main(String[] args){
        int n=8;
        char[][] board=new char[n][n];
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n; j++) {
                board[i][j]='X';
            }
        }
        nQueens(board,0);
    }
}