UVA 11362 / Trie Basic

/***
 created: 2023-01-19-00.43.24
***/

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
template<typename U> using ordered_set=tree<U, null_type,less<U>,rb_tree_tag,tree_order_statistics_node_update>;
#define ll long long
#define all(we) we.begin(),we.end()
#define test int tt; cin>>tt; for(int cs=1;cs<=tt;cs++)
#define nl '\n'


class Node{
public:
    bool endd;
    Node *child[15];
    Node()
    {
        endd=false;
        for(ll i=0;i<13;i++) child[i]=NULL;
    }
};

void Insert(Node *cur,string a)
{
    ll n=a.size();
    for(ll i=0;i<n;i++)
    {
        if(cur->child[a[i]-'0']==NULL)
        {
            cur->child[a[i]-'0'] = new Node();
        }
        cur = cur->child[a[i]-'0'];
    }
    cur->endd=true;
}

bool Search(Node *cur, string a,ll ind)
{
    if(ind==a.size()) return 1;
    if(cur->endd==true) return 0;
    return Search(cur->child[a[ind]-'0'],a,ind+1);
}


int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);


    test
    {
        ll n,m,i,j,k,l;

        cin>>n;

        string a[n+4];

        Node *root = new Node();

        for(i=0;i<n;i++)
        {
            cin>>a[i];
            Insert(root,a[i]);
        }
        l=0;

        for(i=0;i<n;i++)
        {
            if(!Search(root,a[i],0))
            {
                l=1;
                break;
            }
        }

        if(l) cout<<"NO"<<nl;
        else cout<<"YES"<<nl;
    }


    return 0;
}