Phone List

Time Limit: 3000/1000 MS (Java/Others) Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 19272 Accepted Submission(s): 6517

Problem Description

Given a list of phone numbers, determine if it is consistent in the sense that no number is the prefix of another. Let’s say the phone catalogue listed these numbers:

1. Emergency 911

2. Alice 97 625 999

3. Bob 91 12 54 26

In this case, it’s not possible to call Bob, because the central would direct your call to the emergency line as soon as you had dialled the first three digits of Bob’s phone number. So this list would not be consistent.

Input

The first line of input gives a single integer, 1 <= t <= 40, the number of test cases. Each test case starts with n, the number of phone numbers, on a separate line, 1 <= n <= 10000. Then follows n lines with one unique phone number on each line. A phone number is a sequence of at most ten digits.

Output

For each test case, output “YES” if the list is consistent, or “NO” otherwise.

Sample Input

Sample Output




      


       NO
YES

Source

2008 “Insigma International Cup” Zhejiang Collegiate Programming Contest - Warm Up（3）

#define _CRT_secure_NO_WARNINGS
#include <iostream>
#include <cstdio>
#include <cstring>
#include <string>
#include <algorithm>
using namespace std;
char str[10005][15];
struct Trie
{
    int cnt;
    struct Trie *next[10];
    Trie():cnt(0)
    {
        memset(next,0,sizeof(next));
    }
};
Trie *root = NULL;
void Trie_insert(char *str)
{
    Trie *p = root;
    for(int i=0;i<strlen(str);i++)
    {
        if(p -> next[str[i] - '0'] == NULL)
        {
            p -> next[str[i] - '0'] = new Trie;
        }
        p = p -> next[str[i] -'0'];
        p ->cnt++;
    }
}
int Trie_search(char *str)
{
    Trie *p = root;
    for(int i=0;i<strlen(str);i++)
    {
        p = p -> next[str[i] - '0'];
    }
    if(p -> cnt != 1)
        return 0;
    return 1;
}
void del(Trie *root)
{
    if(root == 0)
        return;
    for(int i=0;i<10;i++)
    {
        if(root -> next[i])
            del(root -> next[i]);
    }
    delete root;
}
int main()
{
    int t;
    cin>>t;
    while(t--)
    {
        int n;
        cin>>n;
        root = new Trie;
        for(int i=1;i<=n;i++)
        {
            cin>>str[i];
            Trie_insert(str[i]);
        }
        bool flag = true;
        for(int i=1;i<=n;i++)
        {
            if(!Trie_search(str[i]))
            {
                flag = false;
                break;
            }
        }
        if(flag)
            cout<<"YES"<<endl;
        else
            cout<<"NO"<<endl;
            del(root);
    }
    return 0;
}