91 lines
2.5 KiB
C++
91 lines
2.5 KiB
C++
#include <cstdio>
|
|
#include <cstdlib>
|
|
#include <cstring>
|
|
#include <algorithm>
|
|
#include <iostream>
|
|
#include <vector>
|
|
#define MAXN 505
|
|
#define INF 1000000007
|
|
using namespace std;
|
|
const int dir[4][2]={{1,1},{-1,1},{1,-1},{-1,-1}};
|
|
int n, m,ans;
|
|
int dp[MAXN][MAXN][4],to[4]={3,2,1,0};
|
|
char st[MAXN][MAXN];
|
|
long long p[MAXN], r[MAXN][MAXN], c[MAXN][MAXN];
|
|
void cal(int x,int y,int k)
|
|
{
|
|
int now=dp[x][y][k];
|
|
x+=dir[k][0],y+=dir[k][1];
|
|
while(x>=0&&x<n&&y>=0&&y<m)
|
|
{
|
|
if(dp[x][y][to[k]]<=now) now=dp[x][y][to[k]];
|
|
else if(dp[x][y][to[k]]>=now+2)
|
|
now+=2;
|
|
else ++now;
|
|
ans=max(now,ans);
|
|
x+=dir[k][0],y+=dir[k][1];
|
|
}
|
|
}
|
|
long long ac1(int rr,int x,int y)
|
|
{
|
|
int l=y-x+1;
|
|
if (!x) return r[rr][y];
|
|
return r[rr][y]-r[rr][x-1]*p[l];
|
|
}
|
|
long long ac2(int cc,int x,int y)
|
|
{
|
|
int l=y-x+1;
|
|
if (!x) return c[cc][y];
|
|
return c[cc][y]-c[cc][x-1]*p[l];
|
|
}
|
|
int main()
|
|
{
|
|
int cas;
|
|
scanf("%d",&cas);
|
|
p[0]=1;
|
|
for (int i=1;i<=500;i++) p[i]=p[i-1]*131;
|
|
while (cas--)
|
|
{
|
|
ans=1;
|
|
scanf("%d%d",&n,&m);
|
|
for (int i=0;i<n;i++)
|
|
scanf("%s",st[i]);
|
|
for (int i=0;i<n;i++)
|
|
{
|
|
r[i][0]=st[i][0];
|
|
for (int j=1;j<m;j++)
|
|
r[i][j]=r[i][j-1]*131+st[i][j];
|
|
}
|
|
for (int i=0;i<m;i++)
|
|
{
|
|
c[i][0]=st[0][i];
|
|
for (int j=1;j<n;j++)
|
|
c[i][j]=c[i][j-1]*131+st[j][i];
|
|
}
|
|
for(int i=0;i<n;++i)
|
|
for(int j=0;j<m;++j)
|
|
for(int k=0;k<4;++k)
|
|
{
|
|
int a=k&1?i+1:n-i,b=k<2?m-j:j+1,l=0,r,mid,nx,ny,x2,y2;
|
|
r=min(a-1,b-1);
|
|
while(l<r)
|
|
{
|
|
mid=(l+r+1)/2;
|
|
nx=i+mid*dir[k][0],ny=j+mid*dir[k][1];
|
|
x2=i,y2=j;
|
|
if(x2<nx) swap(x2,nx);
|
|
if(y2<ny) swap(y2,ny);
|
|
if(ac1(i,ny,y2)==ac2(j,nx,x2)) l=mid;
|
|
else r=mid-1;
|
|
}
|
|
dp[i][j][k]=l+1;
|
|
}
|
|
for(int i=0;i<m;++i)
|
|
cal(0,i,2),cal(0,i,0),cal(n-1,i,1),cal(n-1,i,3);
|
|
for(int i=0;i<n;++i)
|
|
cal(i,m-1,2),cal(i,m-1,3),cal(i,0,1),cal(i,0,0);
|
|
printf("%d\n",ans*(ans+1)/2);
|
|
}
|
|
return 0;
|
|
}
|