Queen and Chessboard

#include <bits/stdc++.h>
#define N 4
using namespace std;

int max;

bool is_safe(int board[N][N], int r, int c) {
    for(int j=0 ; j<N ; j++) {   ///Row check
        if(board[r][j]==1)
            return false;
    }
    for(int i=0 ; i<N ; i++) {   ///Column check
        if(board[i][c]==1)
            return false;
    }
    for(int i=r,j=c ; ; i++,j++) {  ///Down Right diagonal check
        if(i==N-1 || j==N-1)
            break;
        if(board[i][j]==1)
            return false;
    }
    for(int i=r,j=c ; ; i--,j--) {  ///Upper Left diagonal check
        if(i==N-1 || j==N-1)
            break;
        if(board[i][j]==1)
            return false;
    }
    for(int i=r,j=c ; ; i++,j--) {  ///Down Left diagonal check
        if(i==N-1 || j==N-1)
            break;
        if(board[i][j]==1)
            return false;
    }
    for(int i=r,j=c ; ; i--,j++) {  ///Upper Right diagonal check
        if(i==N-1 || j==N-1)
            break;
        if(board[i][j]==1)
            return false;
    }
    return true;
}

int solve(int board[N][N],int col,int cnt) {
    if(col==N) {   ///Base Case
        return max;
    }
    for(int i=0 ; i<N ; i++) {
        if(is_safe(board,i,col)) {
            board[i][col]=1;
            cnt++;
            if(max<cnt) max=cnt;
            solve(board,col+1,cnt);
            board[i][col]=0;
            cnt--;
        }
    }
    return max;
}

int main() {
    int board[N][N]={0,0,0,0
                     0,0,0,0
                     0,0,0,0
                     0,0,0,0};
    max=0;
    cout << solve(board,0,0);
    return 0;
}