Grid

input/code.cpp: In function 'int main()':
input/code.cpp:36:8: warning: unused variable 'valid' [-Wunused-variable]
   bool valid = true;
        ^~~~~

#include <iostream>
#include <cmath>
#include <algorithm>
#include <bitset>
#include <vector>
 
using namespace std;
 
typedef long long ll;
 
 
 
 
int main() {
  ll n;
  cin >> n;
 
  vector<bitset<1000> > t (n);
 
  for (int i=0; i<n; i++) {
    cin >> t[i];
  }
 
  bitset<1000> rows;
  bitset<1000> cols;
 
  for (int i=0; i<n; i++) {
    cols[i] = true;
    rows[i] = true;
    for (int j=0; j<n; j++) {
      cols[i] = cols[i] && t[j][i];
      rows[i] = rows[i] && t[i][j];
    }
  }
 
  bool valid = true;
  for (int i=0; i<n; i++) {
    for (int j=0; j<n; j++) {
      if (t[i][j] != (rows[i] || cols[j])) {
	cout << -1 << endl;
	return 0;
      }
    }
  }
 
  ll count = rows.count() + cols.count();
 
  if (count == 2*n) count = n;
 
  cout << count << 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