HDU 2870

HDU 1505加強版

分別枚舉a，b，c3種情況，求最大值‘

#include <iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<string>
#define N 1005
using namespace std;
char map[N][N];
int ans,h[N][N],dpl[N],dpr[N],dp[N][N],n,m;
void solve(char x,char y,char z,char w){
    int i,j,t;
    memset(dp,0,sizeof(dp));
    for(i=1;i<=n;i++){
        for(j=1;j<=m;j++){
            if(map[i][j]==x||map[i][j]==y||map[i][j]==z||map[i][j]==w)
            dp[i][j]=1;
        }
    }
    memset(h,0,sizeof(h));
    for(i=n;i>=1;i--){
        for(j=1;j<=m;j++){
            if(dp[i][j])
            h[i][j]=h[i+1][j]+1;
        }
    }
    for(i=1;i<=n;i++){
        dpl[1]=1;
        dpr[m]=m;
        for(j=2;j<=m;j++){
            t=j;
            while(h[i][t-1]>=h[i][j]&&t>1)
            t=dpl[t-1];
            dpl[j]=t;
        }
        for(j=m-1;j>=1;j--){
            t=j;
            while(h[i][t+1]>h[i][j]&&t<m)
            t=dpr[t+1];
            dpr[j]=t;
        }
        for(j=1;j<=m;j++){
            int tmp=(dpr[j]-dpl[j]+1)*h[i][j];
            if(tmp>ans)
            ans=tmp;
        }
    }
}
int main()
{
    char str[N];
    int i,j;
    while(~scanf("%d%d",&n,&m)){
        ans=0;
        for(i=1;i<=n;i++){
            scanf("%s",str);
            for(j=1;j<=m;j++){
                map[i][j]=str[j-1];
            }
        }
        solve('a','w','y','z');
        solve('b','w','x','z');
        solve('c','x','y','z');
        printf("%d\n",ans);
    }
    return 0;
}