#include "soccer.h"
#include<bits/stdc++.h>
using namespace std;
int ret = 0;
int xx [] = {-1 , 1 , 0 , 0};
int yy[] = {0 , 0 , -1 , 1};
vector<vector<int>> grid;
int get_nest(pair<int ,int> a , pair<int ,int> b)
{
if(a.first == b.first && a.second == b.second)
return 2;
if(a.first <= b.first && b.second <= a.second)
return 0;
swap(a , b);
if(a.first <= b.first && b.second <= a.second)
return 1;
return -1;
}
bool works(int N)
{
vector<pair<int , int>> v(N + 2 , {-1 , -1});
for(int i = 1 ; i <= N ; i++)
{
int ans = 0;
for(int j = 1 ;j <= N+ 1 ; j++)
{
ans+=(grid[i][j] != grid[i][j - 1]);
}
if(ans != 2 && ans!= 0)
{
return 0;
}
int fr = -1;
int lst = -1;
for(int j = 1 ; j <= N ; j++)
{
if(grid[i][j] == 0)
{
if(fr== -1)
fr = j;
lst = j;
}
}
v[i] = {fr , lst};
}
int cnt = 0;
for(int i = 1 ; i <= N + 1 ; i++)
{
cnt+=(v[i - 1].first == -1 && v[i].first != -1) + (v[i - 1].first != -1 && v[i].first == -1);
}
// cout<<cnt<<'\n';
if(cnt != 2)
return 0;
int lst0 = 0;
vector<int> type(N + 1);
for(int i = 2 ; i <= N ; i++)
{
if(v[i].first == -1 || v[i - 1].first == -1)
{
type[i] = 2;
continue;
}
if(v[i].first == v[i - 1].first && v[i].second == v[i - 1].second)
{
type[i] = 2;
continue;
}
type[i] = get_nest(v[i] , v[i - 1]);
if(type[i] == -1)
{
return 0;
}
if(type[i] == 0)
lst0 = i;
}
if(lst0 == 0)
{
return 1;
}
int nb1 = count(type.begin() + 2 , type.begin() + lst0+1 , 1);
if(nb1)
return 0;
vector<vector<int>>l(N + 1);
for(int i = 1 ; i <= N ; i++)
{
if(v[i].first != -1)
{
l[v[i].first].push_back(v[i].second);
}
}
int mxR = 0;
for(int i = N ; i >= 1 ; i--)
{
for(auto r : l[i])
{
if(mxR > r)
{
return 0;
}
}
for(auto r : l[i])
{
mxR = max(mxR , r);
}
}
return 1;
}
int biggest_stadium(int N, std::vector<std::vector<int>> F)
{
ret = 0;
grid.assign(N + 2 ,vector<int> (N + 2 , 1));
for(int i= 1 ; i <= N ; i++)
{
for(int j = 1 ; j <= N ; j++)
{
grid[i][j] = F[i-1][j-1];
ret+=(F[i - 1][j - 1]^1);
}
}
bool check = works(N);
// cout<<check<<'\n';
if(check)
{
assert(ret != 0);
return ret;
}
return 0;
}
/*
--
----
----
------
------
----
*/
