miku

Nqueens.java

@@ -0,0 +1,57 @@
+import java.util.*;
+public class Nqueens{
+    static int n;
+    static int[][] board;
+
+    static boolean isSafe(int r, int c){
+        for(int i=0;i<r;i++){
+            if(board[i][c]==1)
+                return false;
+        }
+        for(int i=r,j=c;i>=0 && j>=0;i--,j--){
+            if(board[i][j]==1)
+                return false;
+        }
+        for(int i=r,j=c;i>=0 && j<n;i--,j++){
+            if(board[i][j]==1)
+                return false;
+        }
+        return true;
+
+    }
+
+    static void solve(int r){
+        if(r==n){
+            for(int i=0;i<n;i++){
+                for(int j=0;j<n;j++){
+                    if(board[i][j]==1){
+                        System.out.print(" Q ");
+                    }else
+                        System.out.print(" . ");
+                }
+                System.out.println();
+            }
+            System.out.println();
+            return;
+            
+        }
+        for(int i=0;i<n;i++){
+            if(isSafe(r,i)){
+                board[r][i] =1;
+                solve(r+1);
+                board[r][i]=0;
+            }
+
+            
+        }
+    }
+    public static void main(String[] args){
+        Scanner sc= new Scanner(System.in);
+        System.out.print("\nEnter n: ");
+        n =sc.nextInt();
+        board = new int[n][n];
+        solve(0);
+        sc.close();
+
+    }
+}