#include <iostream>
#include <fstream>
#include <algorithm>using namespace std;char str[10001][11];
const int sunnum=10,base='0';struct Trie{bool terminal;//int num;Trie *sun[sunnum];
}node[1000000];struct Phone{char num[11];int len;friend bool operator<(const Phone &a,const Phone &b){return a.len<b.len;}
}p[10001];int x=0;
bool result;Trie *NewTrie()
{Trie* temp=node+x++;for(int i=0; i<10; i++){temp->sun[i]=NULL;}temp->terminal=false;return temp;
}void Insert(Trie *root,Phone cur)
{Trie *temp=root;for(int i=0; i<cur.len; i++){  int k=cur.num[i]-base;if(temp->sun[k]==NULL) temp->sun[k]=NewTrie();else{if(temp->sun[k]->terminal==true)   //排序后只需处理这一种情况 即前面的串是后面的串的prefix
            {//return true;result=false;}}temp=temp->sun[k];}temp->terminal=true;
}int main()
{int t,n,i;freopen("acm.txt","r",stdin);scanf("%d",&t);while(t--){Trie *root=NewTrie();scanf("%d",&n);for(i=0; i<n; i++){scanf("%s",p[i].num);p[i].len=strlen(p[i].num);}sort(p,p+n);  //先排序result=true;for(i=0; i<n; i++){Insert(root,p[i]);}if(result) printf("YES\n");else printf("NO\n");}
return 0;
}

#include <iostream>
#include <fstream>
#include <algorithm>using namespace std;char str[10001][11];
const int sunnum=10,base='0';struct Trie{bool terminal;//int num;Trie *sun[sunnum];
}node[1000000];int x=0;
bool result;Trie *NewTrie()
{Trie* temp=node+x++;for(int i=0; i<10; i++){temp->sun[i]=NULL;}temp->terminal=false;return temp;
}bool Insert(Trie *root,char*s)
{Trie *temp=root;while(*s){int k=*s-base;if(*(s+1)=='\0' && temp->sun[k]!=NULL)  //该串是前面某个串的前缀
        {return true;}if(temp->sun[k]==NULL) temp->sun[k]=NewTrie();else{//temp->sun[*s-base]->num++;if(temp->sun[k]->terminal==true)   //别的字符串是该字符串的前缀
            {return true;}}temp=temp->sun[k];s++;}temp->terminal=true;  return false;
}int main()
{int t,n,i;freopen("acm.txt","r",stdin);scanf("%d",&t);while(t--){Trie *root=NewTrie();scanf("%d",&n);for(i=0; i<n; i++){scanf("%s",str[i]);if(Insert(root,str[i])){printf("NO\n");break;}}if(i==n)printf("YES\n");}
return 0;
}