题目地址：http://acm.hdu.edu.cn/showproblem.php?pid=2870
#include<iostream>
#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
#define max3(a,b,c) max(a,max(b,c))
const int maxn=1000+5;
const int A=0,B=1,C=2;
//解的情况肯定都是a，b，c 所以 事先全部替换成a，b，c
char Matrix[maxn][maxn];
int l[maxn],r[maxn],h[maxn][maxn][3],M,N;
bool Check(char c1,char c2){if(c1=='w') return c2=='a'||c2=='b';if(c1=='x') return c2=='b'||c2=='c';if(c1=='y') return c2=='a'||c2=='c';if(c1=='z') return true;return c1==c2;
}
int solve(int a)
{int maxA=0;for(int i=0;i<M;i++){l[0]=0; r[N-1]=N-1;for(int j=1;j<N;j++){int t=j;while(t>0&&Check(Matrix[i][j],a+'a')&&Check(Matrix[i][t-1],a+'a')&&h[i][t-1][a]>=h[i][j][a]) t=l[t-1];l[j]=t;}for(int j=N-2;j>=0;j--){int t=j;while(t<N-1&&Check(Matrix[i][j],a+'a')&&Check(Matrix[i][t+1],a+'a')&&h[i][t+1][a]>=h[i][j][a]) t=r[t+1];r[j]=t;}for(int j=0;j<N;j++)maxA=max(maxA,(r[j]-l[j]+1)*h[i][j][a]);}return maxA;
}
int main()
{while(scanf("%d%d",&M,&N)!=EOF){for(int i=0;i<M;i++){scanf("%s",Matrix[i]);for(int j=0;Matrix[i][j];j++)if(i==0) h[i][j][A]=h[i][j][B]=h[i][j][C]=1;else {h[i][j][A]=Check(Matrix[i-1][j],'a')&&Check(Matrix[i][j],'a')?h[i-1][j][A]+1:1;h[i][j][B]=Check(Matrix[i-1][j],'b')&&Check(Matrix[i][j],'b')?h[i-1][j][B]+1:1;h[i][j][C]=Check(Matrix[i-1][j],'c')&&Check(Matrix[i][j],'c')?h[i-1][j][C]+1:1;}}cout<<max3(solve(A),solve(B),solve(C))<<endl;}return 0;
}