14. N-QUEENS PROBLEM

Code:

import java.util.*;

public class Queens

{

    public static boolean isConsistent(int[] q, int n)

    {

        for (int i = 0; i < n; i++)

            {

            if (q[i] == q[n])             return false;   // same column

            if ((q[i] - q[n]) == (n - i)) return false;   // same major diagonal

            if ((q[n] - q[i]) == (n - i)) return false;   // same minor diagonal

        }

        return true;

    }

    public static void printQueens(int[] q)

    {

        int N = q.length;

        for (int i = 0; i < N; i++)

            {

            for (int j = 0; j < N; j++)

                {

                if (q[i] == j) System.out.print("Q ");

                else           System.out.print("* ");

            }

            System.out.println();

        } 

        System.out.println();

    }

    public static void enumerate(int N)

    {

        int[] a = new int[N];

        enumerate(a, 0);

    }

    public static void enumerate(int[] q, int n)

    {

        int N = q.length;

        if (n == N) printQueens(q);

        else

            {

            for (int i = 0; i < N; i++)

                {

                q[n] = i;

                if (isConsistent(q, n)) enumerate(q, n+1);

            }

        }

    } 

    public static void main(String args[])

    {

            Scanner S=new Scanner(System.in);

        System.out.print("Enter no. of Queens: ");

            int N = S.nextInt();

        enumerate(N);

    }

}

OUTPUT:

Need the code??

Download Link= https://www.dropbox.com/s/b4hzf3ehgar8agf/7%20Four%20Queens.docx?m