Largest Submatrix

#include <bits/stdc++.h>
using namespace std;
#define PB push_back
#define ZERO (1e-10)
#define INF (1<<30)
#define CL(A,I) (memset(A,I,sizeof(A)))
#define DEB printf("DEB!\n");
#define D(X) cout<<"  "<<#X": "<<X<<endl;
#define EQ(A,B) (A+ZERO>B&&A-ZERO<B)
typedef long long ll;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef pair<int,int> ii;
#define IN(n) int n;scanf("%d ",&n);
#define FOR(i, m, n) for (int i(m); i < n; i++)
#define REP(i, n) FOR(i, 0, n)
#define F(n) REP(i, n)
#define FF(n) REP(j, n)
#define FT(m, n) FOR(k, m, n)
#define aa first
#define bb second
void ga(int N,int *A){F(N)scanf("%d",A+i);}
#define MX (32)
int P[MX][MX];
int lrc(int N,int M){
    static int U[MX][MX],L[MX][MX],R[MX][MX];
    int r(0);
    F(N){
        int lo(-1),ro(M);
        FF(M)if(P[i][j])
            U[i][j]=L[i][j]=0,lo=j;
        else U[i][j]=!i?1:U[i-1][j]+1,L[i][j]=!i?lo+1:max(L[i-1][j],lo+1);
        for(int j(M-1);~j;--j)
            if(P[i][j])R[i][j]=N,ro=j;
            else R[i][j]=!i?ro-1:min(R[i-1][j],ro-1)
               ,r=max(r,U[i][j]*(R[i][j]-L[i][j]+1));
    }
    return r;
}
int N,M;
int main(void){
    IN(tt)F(tt){
        M=N=0;
        string s;
        while(getline(cin,s)&&s!=""){
            M=s.size();
            F(M)P[N][i]=s[i]!='1';
            ++N;
        }
        if(i)putchar(10);
        printf("%d\n",lrc(N,M));
    }
    return 0;
}