UVa11488-Hyper Prefix Sets（trie树）

H	Hyper Prefix Sets

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

4 4 0000 0001 10101 010 2 01010010101010101010 11010010101010101010 3 010101010101000010001010 010101010101000010001000 010101010101000010001010 5 01010101010100001010010010100101 01010101010100001010011010101010 00001010101010110101 0001010101011010101 00010101010101001

6 20 66 44

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;
}