Create N-queen_backtracking.cpp

Author: sid779

N-queen_backtracking.cpp

@@ -0,0 +1,68 @@
+#include <bits/stdc++.h>
+#include <iostream>
+using namespace std;
+const int m=10;
+int board[10][10];
+
+void printSolution(int board[][10], int N) 
+{ 
+    for (int i = 0; i < N; i++) 
+    { 
+        for (int j = 0; j < N; j++) 
+            printf(" %d ", board[i][j]); 
+        printf("\n"); 
+    } 
+} 
+
+bool is_attacked(int x,int y,int board[][10], int N){
+    for(int i=0; i<N; i++){
+        for(int j=0; j<N; j++){
+            if(i==x || j==y || (i+j)==(x+y)||(i-j)==(x-y)){
+                if(board[i][j]==1)
+                    return true;
+            }
+        }
+    }
+    return false;
+}
+
+bool N_queens(int board[][m], int row , int N){
+    if(row==N)
+        return true;
+    for(int i=0;i<N;i++){
+        for(int  j=0;j<N;j++){
+            if(is_attacked(i,j,board,N)){
+                continue;
+            }   
+            board[i][j]=1;
+            if(N_queens(board,row+1,N)){
+                return true;
+            }   
+            board[i][j]=0;
+                
+        }
+    }
+    return false;
+}
+
+int main(){
+    int N;
+    cin >> N;
+    
+    
+    for(int i=0;i<=N;i++)
+        for(int j=0;j<=N;j++)
+            board[i][j]=0;
+    
+     
+    
+    if(N_queens(board,0,N)){
+        cout << "YES" << "\n";
+        printSolution(board,N);
+    }
+    else
+        cout << "NO";
+      
+    return 0; 
+    
+}