X

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:

- Emergency 911- Alice 97 625 999- 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

2
3
911
97625999
91125426
5
113
12340
123440
12345
98346

Sample Output

NO
YES

题意：

输入几组字符串，观察是否有包含关系的，并且包含的的部分放在字符串开头

分析：

首先要排序，然后看相邻的是否有包含关系，看find是否返回0；

代码：

#include <bits/stdc++.h>using namespace std;int main(){    int n,m,i,j,t;    vector<string> v;    string s;    while(cin>>n)    {        while(cin>>m)        {            for(i=0;i<m;i++)            {                cin>>s;                v.push_back(s);            }            sort(v.begin(),v.end());            for(i=100,t=1,j=1;j<m;j++)            {                i=v[j].find(v[j-1]);                if(i==0)                {                    cout<<"NO"<<endl;                    t=0;                    break;                }            }            if(t)                cout<<"YES"<<endl;            v.clear();        }    }}

感受：

这个题本来没有思路，我看了下课件，就找到了find,还是记得不好，大多数还是不知道用处，不能真正运用stl