Code:
import java.util.Scanner;
public class Queen {
public static void main(String[] args)
{
System.out.println("Enter nxn order");
Scanner s=new Scanner(System.in); //taking nxn chessboard order from user
int a=s.nextInt();
Queen q = new Queen(a);
q.Nqueens();
}
int[] x;
public Queen(int n) {
x = new int[n]; // total number of lines of chessboard are stored in x
}
public boolean placement(int row, int col) {
for (int i = 0; i < row; i++) {
// check for same row and column in same line or diagonal
if (x[i] == col || (i - row) == (x[i] - col) ||(i - row) == (col - x[i]))
{
return false;
}
}
return true;
}
public void placeNqueens(int r, int n) {
for (int i = 0; i < n; i++) {
//calling the method which checks clash
if (placement(r, i)) { // if row is in no clash, straight or diagonal
x[r] = i; //then assign
if (r == n - 1) {
displayQueens(x);
} else {
placeNqueens(r + 1, n);
}
}
}
}
public void displayQueens(int[] x) { //displaying Queens method
int n = x.length;
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
if (x[i] == j) {
System.out.print("Q ");
} else {
System.out.print("* ");
}
}
System.out.println();
}
System.out.println();
}
public void Nqueens() {
placeNqueens(0, x.length);
}
}
Output:
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