Grid

#include <bits/stdc++.h>
using namespace std;
int n;
 
string m[1010];
bool ch[1010][1010];
 
int main(){
    ios_base::sync_with_stdio(0);cin.tie(0);
    cin >> n;
    for (int i=0;i<n;++i)cin>>m[i];
    int no=0;
    for (int i=0;i<n;++i){
        bool tk=1;
        for (int j=0;j<n;++j){
            if (m[i][j]!='1') tk=0;
        }
        if (tk){
            ++no;
            for (int j=0;j<n;++j){
                ch[i][j]=1;
            }
        }
    }
    for (int j=0;j<n;++j){
        bool tk=1;
        for (int i=0;i<n;++i){
            if (m[i][j]!='1') tk=0;
        }
        if (tk){
            ++no;
            for (int i=0;i<n;++i){
                ch[i][j]=1;
            }
        }
    }
    for (int i=0;i<n;++i){
        for (int j=0;j<n;++j){
            if (m[i][j]=='1' && !ch[i][j]) no=-1;
        }
    }
    if (no==2*n) no=n;
    cout << no << "\n";
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED

Test 16

Verdict: ACCEPTED

Test 17

Verdict: ACCEPTED

Test 18

Verdict: ACCEPTED

Test 19

Verdict: ACCEPTED

Test 20

Verdict: ACCEPTED

Test 21

Verdict: ACCEPTED

Test 22

Verdict: ACCEPTED