悬线法
#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;
int n, m, h[2005][2005], l[2005][2005], r[2005][2005], uu, iii=0, jjj=0;
bool a[2005][2005];
void rn(int &x){
char ch=getchar();
x = 0;
while(ch<‘0‘ || ch>‘9‘) ch = getchar();
while(ch>=‘0‘ && ch<=‘9‘){
x = x * 10 + ch - ‘0‘;
ch = getchar();
}
}
void work(){
int ans=0, maxn=0;
memset(h, 0, sizeof(h));
for(int i=1; i<=n; i++){
int x=1;
for(int j=1; j<=m; j++)
if(a[i][j]) l[i][j] = x;
else l[i][j] = 1, x = j + 1;
x = m;
for(int j=m; j>=1; j--)
if(a[i][j]) r[i][j] = x;
else r[i][j] = m, x = j - 1;
}
for(int i=1; i<=m; i++) l[0][i] = 1, r[0][i] = m;
for(int i=1; i<=n; i++)
for(int j=1; j<=m; j++)
if(a[i][j]){
h[i][j] = h[i-1][j] + 1;
l[i][j] = max(l[i][j], l[i-1][j]);
r[i][j] = min(r[i][j], r[i-1][j]);
ans = max(ans, (r[i][j]-l[i][j]+1)*h[i][j]);
maxn = max(maxn, min(h[i][j], (r[i][j]-l[i][j]+1)));
}
iii = max(iii, maxn*maxn);
jjj = max(jjj, ans);
}
int main(){
cin>>n>>m;
for(int i=1; i<=n; i++)
for(int j=1; j<=m; j++){
rn(uu);
a[i][j] = uu;
if((i+j)%2==0) a[i][j] ^= 1;
}
work();
for(int i=1; i<=n; i++)
for(int j=1; j<=m; j++)
a[i][j] ^= 1;
work();
cout<<iii<<endl<<jjj<<endl;
return 0;
}