Grid

#include <iostream>
#include <string>
#include <stdio.h>
#include <math.h>
#include <vector>

using namespace std;

int main() {
    int n;
    cin >> n;
    char c;
    vector<bool> m(n * n, false);
    vector<bool> rows(n, true); // black rows

    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            cin >> c;
            if (c == '1') {
                m[i * n + j] = true;
            } else {
                rows[i] = false;
            }
        }
    }

    if (n == 1) {
        if (m[0]) cout << 1 << endl;
        else cout << 0 << endl;
        return 0;
    }

    int blackColCount = 0;
    
    for (int j = 0; j < n; j++) {
        bool isBlack = true;
        bool isValid = true;
        for (int i = 0; i < n; i++) {
            if (m[i * n + j]) {
                if (!rows[i]) isValid = false;
            } else {
                isBlack = false;
            }
        }
        if (!isBlack && !isValid) {
            cout << -1 << endl;
            return 0;
        }
        if (isBlack) blackColCount++;
    }
    if (blackColCount == n) {

        cout << n << endl;
        return 0;
    }

    int blackRowCount = 0;

    for (int i = 0; i < n; i++) {
        if (rows[i]) blackRowCount++;
    }
    cout << blackColCount + blackRowCount << endl;
}

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