Added N-Queen in cpp

Author: varun514

Backtracking/N-Queen/C++/N-Queen.cpp

@@ -0,0 +1,63 @@
+#include<iostream>
+
+using namespace std;
+#define N 5
+
+void printBoard(int board[N][N]){
+    for(int i=0;i<N;i++){
+        for(int j=0;j<N;j++)
+            cout<<board[i][j]<<" ";
+        cout<<endl;
+    }
+}
+
+bool isValid(int board[N][N], int row, int col){
+    for(int i=0;i<col;i++)
+        if(board[row][i])
+            return false;
+
+    for(int i=row,j=col;i>=0 && j>=0;i--,j--)
+        if(board[i][j])
+            return false;
+    
+    for(int i=row,j=col;j>=0 && i<N;i++,j--)
+        if(board[i][j])
+            return false;
+    
+    return true;
+}
+
+bool solveNQueen(int board[N][N], int col){
+    if(col>=N)
+        return true;
+    
+    for(int i=0;i<N;i++){
+        if(isValid(board, i, col)){
+            board[i][col] = 1;
+            if(solveNQueen(board,col+1))
+                return true;
+
+            board[i][col] = 0;
+        }
+    }
+    return false;
+}
+
+bool checkSolution(){
+    int board[N][N];
+    for(int i=0;i<N;i++)
+        for(int j=0;j<N;j++)
+            board[i][j] = 0;
+
+    if(!solveNQueen(board,0)){
+        cout<<"Solution does not exist"<<endl;
+        return false;
+    }
+
+    printBoard(board);
+    return true;
+}
+
+int main(){
+    checkSolution();
+}