Longest

#include<stdio.h>
int max(int a,int b){
    return (a > b ? a : b);
}
int max4(int a,int b,int c,int d){
    return max(max(a,b),max(c,d));
}
int main(){
    int T;
    scanf("%d",&T);
    for(int t = 0 ; t < T ; t ++){
        int n,m;
        scanf("%d %d",&n,&m);
        char board[n][m+1];
        for(int i=0;i<n;i++){
            scanf("%s",board[i]);
        }
        int ngurUp[n][m];
        for(int i=0;i<n;i++)for(int j=0;j<m;j++)ngurUp[i][j] = (board[i][j] == '1' ? i : -1);
        for(int j=0;j<m;j++){
            for(int i=1;i<n;i++){
                if(ngurUp[i-1][j] != -1 && ngurUp[i][j] != -1){
                    ngurUp[i][j] = ngurUp[i-1][j];
                }
            }
        }
        int ngurDown[n][m];
        for(int i=0;i<n;i++)for(int j=0;j<m;j++)ngurDown[i][j] = (board[i][j] == '1' ? i : -1);
        for(int j=0;j<m;j++){
            for(int i=n-2;i>=0;i--){
                if(ngurDown[i+1][j] != -1 && ngurDown[i][j] != -1){
                    ngurDown[i][j] = ngurDown[i+1][j];
                }
            }
        }
        int ans = -2e9;
        for(int i=0;i<n;i++){
            int temp = 0;
            for(int j=0;j<m;j++){
                temp++;
                temp*=board[i][j] - '0';
                if(temp == 0)continue;
                ans = max4(ans,temp,temp + (i - ngurUp[i][j]),temp + (ngurDown[i][j] - i));
            }
        }
        for(int i=0;i<n;i++){
            int temp = 0;
            for(int j=m-1;j>=0;j--){
                temp++;
                temp*=board[i][j] - '0';
                if(temp == 0)continue;
                ans = max4(ans,temp,temp + (i - ngurUp[i][j]),temp + (ngurDown[i][j] - i));
            }
        }
        printf("%d\n",ans);
    }
    return 0;
}