Prefix goodness of a set string is length of longest common prefix*number of strings in the set. For example the prefix goodness of the set {000,001,0011} is 6.You are given a set of binary strings. Find the maximum prefix goodness among all possible subsets of these binary strings.

Input
First line of the input contains T(≤20) the number of test cases. Each of the test cases start with n(≤50000) the number of strings. Each of the next n lines contains a string containing only 0 and 1. Maximum length of each of these string is 200.

Output
For each test case output the maximum prefix goodness among all possible subsets of n binary strings.

Sample Input Output for Sample Input

Problem Setter : Abdullah Al Mahmud
Special Thanks : Manzurur Rahman Khan

#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
#include <string>
#include <algorithm>
#include <queue>
using namespace std;

const int maxn = 5000000;
vector<string> vs;
int cnt,ans,n;
int ch[maxn][2];
int val[maxn];

inline int getIdx(char a){
    return a-'0';
}
void insert(string st){
    int u = 0;
    for(int i = 0; i < st.size(); i++){
        int k = getIdx(st[i]);
        if(!ch[u][k]){
            memset(ch[cnt],0,sizeof ch[cnt]);
            val[cnt]++;
            ans = max(ans,val[cnt]*(i+1));
            ch[u][k] = cnt++;
        }else{
            val[ch[u][k]]++;
            ans = max(ans,val[ch[u][k]]*(i+1));
        }
        u = ch[u][k];
    }
}
int main(){

    int ncase;
    cin >> ncase;
    while(ncase--){
        vs.clear();
        memset(val,0,sizeof val);
        memset(ch[0],0,sizeof ch[0]);
        cnt = 1;
        ans = 0;
        cin >> n;
        while(n--){
            string st;
            cin >> st;
            insert(st);
        }
        cout<<ans<<endl;
    }
    return 0;
}