D. Table with Letters - 2

http://codeforces.com/contest/253/problem/D

挺麻烦的一道题

代码：

#include<iostream>

#include<cstdio>

#include<cstring>

#include<string>

#include<map>

#include<vector>

#include<stack>

#include<queue>

#include<algorithm>

#define LL long long

using namespace std;

const int INF=0x3f3f3f3f;

const int N=405;

int sum[N][N];

char s[N][N];

int level[N];

int n,m,k;

LL ans;

bool OK(int x1,int y1,int x2,int y2)

{

    if(x1==x2)

    return true;

    int tmp=sum[x2][y2]-sum[x2][y1-1]-sum[x1-1][y2]+sum[x1-1][y1-1];

    if(tmp<=k)

    return true;

    return false;

}

void Fsearch(char w)

{//cout<<w<<endl;

     for(int j1=1;j1<=m;++j1)

     for(int j2=j1+1;j2<=m;++j2)

     {

         int I=0;

         for(int i=1;i<=n;++i)

         {

             if(s[i][j1]==w&&s[i][j2]==w)

             level[I++]=i;

         }

         int l=0;

         int r=1;

         while(r<I)

         {

             if(OK(level[l],j1,level[r],j2))

             {

                 ans+=(r-l);

                 ++r;

             }

             else

             {

                 ++l;

             }

         }

     }

}

int main()

{

    //freopen("data.in","r",stdin);

    freopen("input.txt","r",stdin);

    freopen("output.txt","w",stdout);

    while(scanf("%d %d %d",&n,&m,&k)!=EOF)

    {

        getchar();

        memset(sum,0,sizeof(sum));

        bool had[27];

        memset(had,false,sizeof(had));

        for(int i=1;i<=n;++i)

        gets(s[i]+1);

        for(int i=1;i<=n;++i)

        for(int j=1;j<=m;++j)

        {

            had[s[i][j]-'a']=true;

            if(s[i][j]=='a')

            sum[i][j]=1;

        }

        for(int i=1;i<=n;++i)

        for(int j=1;j<=m;++j)

        {

            sum[i][j]+=(sum[i-1][j]+sum[i][j-1]-sum[i-1][j-1]);

        }

        ans=0;

        for(char w='a';w<='z';++w)

        if(had[w-'a'])

        Fsearch(w);

        printf("%I64d\n",ans);

    }

    return 0;

}