#include <bits/stdc++.h>
#include "soccer.h"
#define ar array
#define ll long long
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
using namespace std;
template<typename T> bool ckmin(T &a, const T &b) { return a > b ? a = b, 1 : 0; }
template<typename T> bool ckmax(T &a, const T &b) { return a < b ? a = b, 1 : 0; }
const int nax = 31;
int dp[nax][nax][nax][nax];
int biggest_stadium(int n, std::vector<std::vector<int>> F)
{
int sx = -1, sy = -1;
bool one = 1;
for (int i = 0; i < n; i++) for (int j = 0; j < n; j++) {
if (F[i][j]) {
if (~sx) one = 0;
sx = i, sy = j;
}
}
if (one) {
return n*n - min(sx+1, n-sx) * min(sy+1, n-sy);
}
if (n > 30) {
vector<ar<int, 2>> ints(n);
int L = -1, R = -1;
for (int i = 0; i < n; i++) {
int u = 0;
for (int j = 0; j < n; j++) if (!F[i][j]) {
int r = j;
while (r+1 < n && !F[i][r+1]) r++;
ints[i] = {j, r};
if (++u == 2) return 0;
j = r;
}
if (u) {
if (!~L) L = i;
else {
if (R != i-1) return 0;
}
R = i;
}
}
int len = -1, idx = -1;
for (int i = L; i <= R; i++) {
if (ckmax(len, ints[i][1] - ints[i][0])) idx = i;
}
for (int i = idx-1; i >= L; i--) {
if (!(ints[i][0] >= ints[i+1][0] && ints[i][1] <= ints[i+1][1])) {
return 0;
}
}
for (int i = idx+1; i <= R; i++) {
if (!(ints[i][0] >= ints[i-1][0] && ints[i][1] <= ints[i-1][1])) {
return 0;
}
}
for (int i = L; i <= R; i++) {
for (int j = L; j <= R; j++) {
auto [L1, R1] = ints[i];
auto [L2, R2] = ints[j];
if (L1 > L2 || (L1 == L2 && R1 < R2)) swap(L1, L2), swap(R1, R2);
if (R1 < R2) return 0;
}
}
int tot = 0;
for (int i = 0; i < n; i++) for (int j = 0; j < n; j++) tot += !F[i][j];
return tot;
}
memset(dp, 0xc1, sizeof(dp));
vector<vector<int>> to(n, vector<int>(n, -1));
for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) if (!F[i][j]) {
int r = j;
while (r+1 < n && !F[i][r+1]) r++;
for (int k = j; k <= r; k++) to[i][k] = r;
dp[i][i][j][r] = r-j+1;
j = r;
}
}
for (int len = 1; len < n; len++) {
for (int i = 0; i+len-1 < n; i++) {
int j = i+len-1;
for (int l = 0; l < n; l++) {
for (int r = l; r < n; r++) if (dp[i][j][l][r] > 0) {
if (i) {
for (int z = l; z <= r; z++) if (~to[i-1][z]) {
int new_r = min(to[i-1][z], r);
ckmax(dp[i-1][j][z][new_r], dp[i][j][l][r] + new_r - z + 1);
}
}
if (j+1 < n) {
for (int z = l; z <= r; z++) if (~to[j+1][z]) {
int new_r = min(to[j+1][z], r);
ckmax(dp[i][j+1][z][new_r], dp[i][j][l][r] + new_r - z + 1);
}
}
}
}
}
}
int ans = 0;
for (int i = 0; i < n; i++) for (int j = i; j < n; j++) for (int k = 0; k < n; k++) for (int l = k; l < n; l++) ckmax(ans, dp[i][j][k][l]);
return ans;
}
