Codeforces 372B Counting Rectangles is Fun

http://codeforces.com/problemset/problem/372/B

题意:每次给出一个区间，求里面有多少个矩形

思路:预处理，sum[i][j][k][l]代表以k,l为右下角，左上角不超过i,j有多少矩形，然后询问的时候枚举右下角就可以了

 #include<cstdio>
 #include<cmath>
 #include<algorithm>
 #include<cstring>
 #include<iostream>
 int n,m,T;
 int sum[][][][],l[][];
 char s[];
 int read(){
     int t=,f=;char ch=getchar();
     while (ch<''||ch>''){if (ch=='-') f=-;ch=getchar();}
     while (''<=ch&&ch<=''){t=t*+ch-'';ch=getchar();}
     return t*f;
 }
 void init(){
     for (int i=;i<=n;i++){
         scanf("%s",s+);
         for (int j=;j<=m;j++){
          if (s[j]=='') continue;
          if (s[j-]=='') l[i][j]=l[i][j-]+;
          else l[i][j]=;
         }
     }
     for (int i=;i<=n;i++)
      for (int j=;j<=m;j++)
       for (int k=i;k<=n;k++)
        for (int L=j;L<=m;L++){
             int tmp=<<;
             int ss=;
             for (int x=k;x>=i;x--){
                 int ll=std::min(L-j+,l[x][L]);
                 tmp=std::min(tmp,ll);
                 ss+=tmp;
             }
             sum[i][j][k][L]=ss;
        }
 }
 int main(){
     n=read();m=read();T=read();
     init();
     while (T--){
         int x1=read(),y1=read(),x2=read(),y2=read(),ans=;
         for (int i=x1;i<=x2;i++)
          for (int j=y1;j<=y2;j++)
           ans+=sum[x1][y1][i][j];
         printf("%d\n",ans);
     }
     return ;
 }