#include <bits/stdc++.h>
#include "soccer.h"
using namespace std;
using pii = pair<int, int>;
constexpr pii id = {-1, -1};
bool inside(pii a, pii b){
if(a.first == -1) return true;
if(b.first == -1) return false;
return b.first <= a.first && a.second <= b.second;
}
int biggest_stadium(int N, vector<vector<int>> F){
vector<pii> v(N);
int flag = 0;
int start = 0;
for(int i = 0; i < N; i++){
int l = -1, r = -1;
for(int j = 0; j < N; j++){
if(F[i][j] == 0){
if(l == -1) l = j;
r = j;
}
}
for(int j = l; j < r+1; j++){
if(F[i][j]) return 0;
}
v[i] = {l, r};
if(flag == 0 && l != -1) flag = 1;
if(flag == 1 && l == -1) flag = 2;
if(flag == 2 && l != -1) return 0;
if(inside(v[start], v[i])) start = i;
}
int lo = start, hi = start;
while(true){
pii le = (lo >= 0 ? v[lo] : id);
pii ri = (hi < N ? v[hi] : id);
if(le == id && ri == id) break;
if(inside(le, ri)) hi++;
else if(inside(ri, le)) lo--;
else return 0;
}
int cnt = 0;
for(int i = 0; i < N; i++) for(int j = 0; j < N; j++) cnt += F[i][j]^1;
return cnt;
}
