See the problem UVa-11488
>>>This problem has been solved using "Trie". So if you don't known with "Trie", you should not try to understand this solution.<<<
#include<bits/stdc++.h>
#define ll long long
using namespace std;
ll cur, last, ss, sss, ans, mx;
string s;
struct node{
int next[2];
long long cnt;
}ar[10000009];
void new_trie(int cur){
ar[cur].next[0]=-1;
ar[cur].next[1]=-1;
ar[cur].cnt=1;
}
int insrt(){
ss=s.size(), cur=0;
for(int k=0; k<ss; k++){
int x=(int)s[k]-48;
if(ar[cur].next[x]==-1){
ar[cur].next[x]=last;
new_trie(last++);
cur=ar[cur].next[x];
}
else{
cur=ar[cur].next[x];
ar[cur].cnt++;
mx=(k+1)*ar[cur].cnt;
ans=max(mx, ans);
}
}
sss=max(ss, sss);
}
int main(){
long long t, n;
cin>>t;
while(t--){
ans=0, mx=0, last=1, sss=0;
new_trie(0);
cin>>n;
while(n--){
cin>>s;
insrt();
}
cout<<max(ans, sss)<<endl;
}
return 0;
}