1 #include<cstring>
 2 #include<cstdio>
 3 #include<cstdlib>
 4 using namespace std;
 5 const int maxn=1005;
 6 int n,m,x,y;
 7 __int64 map[maxn][maxn];
 8 int main(){
 9     int cas;
10     //system("cd desktop\\codeblock\\problem");
11     //system("call test.in");
12     //system("pause");
13     //freopen("test.in","r",stdin);
14     scanf("%d",&cas);
15       while(cas--){
16         scanf("%d%d%d%d",&n,&m,&x,&y);
17          memset(map,0,sizeof(map));
18         for(int i=1;i<=n;i++){
19           for(int j=1;j<=m;j++){
20             scanf("%I64d",&map[i][j]);
21             map[i][j]+=(map[i-1][j]+map[i][j-1]-map[i-1][j-1]);
22           }
23          }
24         __int64 ans=0;
25         __int64 val ;
26         for(int i=x;i<=n;i++){
27           for(int j=y;j<=m;j++){
28             val=map[i][j]-map[i-x][j]-map[i][j-y]+map[i-x][j-y];
29             if(ans<val)ans=val;
30           }
31         }
32         printf("%I64d\n",ans);
33       }
34  return 0;
35 }