/**
找最大的纯0 纯1 或01交叉的矩阵,01交叉的要是方阵
前两种单调栈或单调队列
第三种dp
dp[i][j] = min(dp[i][j-1],dp[i-1][j]) + (mat[i][j] == mat[i-k][j-k])
*/
#include <stdio.h>
#include <iostream>
#include <string.h>
using namespace std;
#define N 1100
char s[N][N];
int mat[N][N];
int lef[N],rig[N],dp[N][N];
int m,n,hg[2][N];
int f(int flag)
{
memset(hg,0,sizeof(hg));
int j;
int cur,pre,tmp,res = 0;
for(int i = 1; i <= n; ++i)
{
cur = (i & 1);
pre = !cur;
for(j = 1; j <= m; ++j)
if(mat[i][j] == flag)
hg[cur][j] = hg[pre][j] + 1;
else
hg[cur][j] = 0;
for(j =