#include <bits/stdc++.h>
using namespace std;
struct Pos {
int x, y;
Pos(int x, int y) : x(x), y(y) {}
};
bool FIELD[2001][2001] = {0};
// bool empty(int a, int b, int x, int y) {
// assert(a == x || b == y); // only 1d queries
// if (a == x)
// for (int i = min(b, y); i <= max(b, y); i++)
// if (FIELD[a][i]) return false;
// if (b == y)
// for (int i = min(a, x); i <= max(a, x); i++)
// if (FIELD[i][b]) return false;
// return true;
// }
int biggest_stadium(int N, vector<vector<int>> F) {
vector<Pos> trees;
for (int i = 0; i < N; i++) for (int j = 0; j < N; j++) {
if (F[i][j] == 1) trees.push_back({i, j});
FIELD[i][j] = F[i][j];
}
for (auto tree : trees) {
cerr << tree.x << " " << tree.y << endl;
}
if (trees.size() == 0) return N * N;
if (trees.size() == 1) {
int x = trees[0].x, y = trees[0].y;
int n = N - 1;
int a = (abs(x - 0) + 1) * (abs(y - 0) + 1);
int b = (abs(x - 0) + 1) * (abs(y - n) + 1);
int c = (abs(x - n) + 1) * (abs(y - 0) + 1);
int d = (abs(x - n) + 1) * (abs(y - n) + 1);
return N * N - min({a, b, c, d});
}
const int MAXN = 500;
set<set<pair<int, int>>> cover;
set<pair<int, int>> last;
for (int i = 0; i < N; i++) for (int j = 0; j < N; j++) {
if (FIELD[i][j] == 1) continue;
const int DIRS[4][2] = {{0, 1}, {0, -1}, {1, 0}, {-1, 0}};
// x, y and direction and the kick
// 0 = first kick, 1 = second kick
queue<tuple<int, int, int, bool>> q;
bool used[MAXN][MAXN][4][2] = {0};
bool visited[MAXN][MAXN] = {0};
set<pair<int, int>> vis;
visited[i][j] = true;
vis.insert({i, j});
for (int d = 0; d < 4; d++) {
used[i][j][d][0] = true;
q.push({i, j, d, 0});
}
while (!q.empty()) {
auto [x, y, d, k] = q.front(); q.pop();
x += DIRS[d][0];
y += DIRS[d][1];
if (x < 0 || x >= N || y < 0 || y >= N) continue;
if (FIELD[x][y]) continue;
if (used[x][y][d][k]) continue;
visited[x][y] = true;
vis.insert({x, y});
used[x][y][d][k] = true;
q.push({x, y, d, k});
if (k == true) continue;
for (int d = 0; d < 4; d++) {
used[x][y][d][1] = true;
q.push({x, y, d, 1});
}
}
cover.insert(vis);
last = vis;
cerr << "ceverage from " << i << " " << j << endl;
for (int a = 0; a < N; a++) {
for (int b = 0; b < N; b++) {
if (a == i && b == j) cerr << "@";
else if (FIELD[a][b]) cerr << "#";
else if (visited[a][b]) cerr << "+";
else cerr << " ";
cerr << " ";
}
cerr << '\n';
}
}
if (cover.size() == 1 && last.size() == N * N - trees.size())
return N * N - trees.size();
return 0;
// for (int a = 0; a < N; a++) for (int b = 0; b < N; b++) {
// for (int x = 0; x < N; x++) for (int y = 0; y < N; y++) {
// // going throgh (a, y)
// if (a == x && b == y) continue;
// if (FIELD[a][b] || FIELD[x][y]) continue;
// if ((empty(a, b, a, y) && empty(x, y, a, y))
// || empty(a, b, x, b) && empty(x, y, x, b)) {
// continue;
// } else {return 0;}
// }
// }
// return N * N - trees.size();
}
