LA-3029(扫描线)

#include <bits/stdc++.h>
using namespace std;

#define For(i,j,n) for(int i=j;i<=n;i++)
#define mst(ss,b) memset(ss,b,sizeof(ss));

typedef  long long LL;

template<class T> void read(T&num) {
    char CH; bool F=false;
    for(CH=getchar();CH<‘0‘||CH>‘9‘;F= CH==‘-‘,CH=getchar());
    for(num=0;CH>=‘0‘&&CH<=‘9‘;num=num*10+CH-‘0‘,CH=getchar());
    F && (num=-num);
}
int stk[70], tp;
template<class T> inline void print(T p) {
    if(!p) { puts("0"); return; }
    while(p) stk[++ tp] = p%10, p/=10;
    while(tp) putchar(stk[tp--] + ‘0‘);
    putchar(‘\n‘);
}

const LL mod=1e9+7;
const double PI=acos(-1.0);
const LL inf=1e18;
const int N=2e5+10;
const int maxn=1005;
const double eps=1e-10;

char mp[maxn][maxn],s[2*maxn];

int up[maxn][maxn],le[maxn][maxn],ri[maxn][maxn],n,m;
int main()
{
        int t;
        read(t);
        while(t--)
        {
            read(n);read(m);
      mst(up,0);
      mst(le,0);
      mst(ri,0);
      For(i,1,n)
      {
        For(j,1,m)
        {
          scanf("%s",s);
          mp[i][j]=s[0];
        }
      }
      For(i,1,n)
      {
          For(j,1,m)
          {
            if(mp[i][j]==‘F‘)up[i][j]= i==1?1:up[i-1][j]+1;
            else up[i][j]=0;
          }
      }
      int ans =0;
      For(i,1,n)
      {
        int lo=0,ro=m+1;
        For(j,1,m)
        {
          if(mp[i][j]==‘F‘)le[i][j]= i==1?lo+1:max(lo+1,le[i-1][j]);
          else le[i][j]=j+1,lo=j;
        }
        for(int j=m;j>0;j--)
        {
          if(mp[i][j]==‘F‘)ri[i][j]= i==1?ro-1:min(ro-1,ri[i-1][j]);
          else ri[i][j]=j-1,ro=j;
        }
        For(j,1,m)
        {
          if(mp[i][j]==‘F‘)ans=max(ans,(ri[i][j]-le[i][j]+1)*up[i][j]);
        }
      }
      cout<<3*ans<<"\n";
        }

        return 0;
}