UV 11488-Hyper Prefix Sets (Trie)

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 {000,001,001 1} 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 Kha

Trie is used to calculate the number of occurrences of each substring. Each node stores two pieces of information. This node represents the length of the substring, the number of occurrences of the substring, and finally scans all nodes, find the maximum length * times.

#include <cstdio>#include <cstring>#include <algorithm>#include <iostream>using namespace std;const int maxn = 1000000 + 5;struct Node{    int sum,len;}node[maxn];int trie[maxn][2];int sz;int idx(char c){ return c - '0';}void insert(char *s){    int u = 0,len = strlen(s);    for(int i = 0;i < len;i++){        int c = idx(s[i]);        if(!trie[u][c]){            trie[u][c] = sz;            node[sz].len = i+1;            sz++;        }        u = trie[u][c];        node[u].sum++;    }}int main(){    int t,n;    char str[205];    scanf("%d",&t);    while(t--){        scanf("%d",&n);        memset(trie,0,sizeof(trie));        for(int i = 0;i < maxn;i++) node[i].sum = 0;        sz = 1;        while(n--){            scanf("%s",str);            insert(str);        }        int ans = -1;        for(int i = 1;i < sz;i++){            ans = max(ans,node[i].len*node[i].sum);        }        printf("%d\n",ans);    }    return 0;}