USACO 2016 January Contest Fort Moo (bzoj4506)

#include <stdio.h>
#include <algorithm>
#include <cstring>
#include <cmath>
#include <queue>
#include <vector>
using namespace std;
const int maxn=2e2+10;
int n,m,ans;
int b[maxn][maxn];
char a[maxn][maxn]; 
template <class T> void read(T&x)
{
  x=0;char c=getchar();int f=0;
  while(c<‘0‘||c>‘9‘){f|=(c==‘-‘);c=getchar();}
  while(c>=‘0‘&&c<=‘9‘)x=(x<<3)+(x<<1)+(c^48),c=getchar();
  x=f?-x:x;
}
int main()
{
  read(n);read(m);
  for(int i=1;i<=n;i++)scanf("%s",a[i]+1);
  for(int j=1;j<=m;j++)
   for(int i=1;i<=n;i++)
    if(a[i][j]==‘X‘)b[i][j]=b[i-1][j]+1;
    else b[i][j]=b[i-1][j];
  for(int i=1;i<=n;i++)
   for(int j=i;j<=n;j++)
   {
        int x=0,y=0;
        for(int k=1;k<=m;k++)
         if(b[j][k]-b[i-1][k]==0)
         {
             x=max(x,k);y=x;
             while(x<m&&a[i][x+1]==‘.‘&&a[j][x+1]==‘.‘)
             {
               x++;
               if(b[j][x]-b[i-1][x]==0)y=x;
             }
             ans=max(ans,(j-i+1)*(y-k+1));
         }
   }
  printf("%d",ans);
  return 0;
}