BZOJ 1057: [ZJOI2007]棋盘制作

#include <iostream>
#include <cstdio>
#include <cstring>
#include <string.h>
#include <queue>
#include <vector>
#include <algorithm>
#include <cassert>
#include <set>
#include <map>
#include <cmath>
#include <ctime>
using namespace std;
#define rep(i,a,b) for(int i=(a);i<(b);++i)
#define rrep(i,a,b) for(int i=(a);i>=(b);--i)
#define clr(a,x) memset(a,(x),sizeof(a))
#define eps 1e-8
#define LL long long
#define mp make_pair
const int maxn=2000+5;
int h[maxn],l[maxn],r[maxn];
int a[maxn][maxn];

void read_int(int & x)
{
char ch=getchar();
while(ch<'0'||ch>'9') ch=getchar();
x=ch-'0'; ch=getchar();
while('0'<=ch&&ch<='9') {
x=x*10+ch-'0'; ch=getchar();
}
}

int main()
{
//  freopen("in.txt","r",stdin);
int n,m;
while(scanf("%d%d",&n,&m)==2) {
rep(i,1,n+1) rep(j,1,m+1) read_int(a[i][j]);
int square=0,rect=0; clr(h,0);
rep(i,1,n+1)  {
rep(j,1,m+1)
if(a[i][j]!=a[i-1][j]) ++h[j];
else h[j]=1;
rep(j,1,m+1) l[j]=r[j]=j;
rep(j,2,m+1)
while(l[j]-1>=1&&h[l[j]-1]>=h[j]&&a[i][l[j]-1]!=a[i][l[j]]) l[j]=l[l[j]-1];
rrep(j,m-1,1)
while(r[j]+1<=m&&h[r[j]+1]>=h[j]&&a[i][r[j]+1]!=a[i][r[j]]) r[j]=r[r[j]+1];
rep(j,1,m+1) {
square=max(square,min(h[j],r[j]-l[j]+1)*min(h[j],r[j]-l[j]+1));
rect=max(rect,h[j]*(r[j]-l[j]+1));
}
}
printf("%d\n%d\n",square,rect);
}

}