trie

#include<bits/stdc++.h>
using namespace std;

const int k = 26;

struct Vertex {
	int next[k];
	bool leaf = false;
	Vertex() {
		fill(next,next + k,-1);
	}
};

vector<Vertex> trie(1);

void insert (string const& s) {
	int v = 0;
	for (int i = 0; i < (int) s.size(); ++i) {
		if (trie[v].next[s[i] - '0'] == -1) {
			trie[v].next[s[i] - '0'] = trie.size();
			trie.emplace_back();
		}
		v = trie[v].next[s[i] - '0'];
	}
	trie[v].leaf = true;
}


bool find (string const& s) {
	int v = 0;
	for (int i = 0; i < (int) s.size(); ++i) {
		if (trie[v].next[s[i] - '0'] == -1) return false;
		v = trie[v].next[s[i] - '0'];
		if ((int) s.size() == i + 1 and trie[v].leaf) return false;
	}
	return true;
}

int main () {
	 ios::sync_with_stdio(false);
	 cin.tie(nullptr);
	 cout.tie(nullptr);
	 int T;
	 cin >> T;
	 for (int test_case = 1; test_case <= T; ++test_case) {
		int n;
		cin >> n;
		vector<pair<int,string>> s;
		for (int i = 0; i < n; ++i) {
			string in;
			cin >> in;
			s.push_back(make_pair((int) in.size(),in));
		}
		sort (s.rbegin(),s.rend());
		bool yes = true;
		for (int i = 0; i < (int) s.size(); ++i) {
			if (find(s[i].second)) {
				yes = false;
				break;
			}
			insert(s[i].second);
		}
		cout << (yes ? "YES\n" : "NO\n");
	 }
	 //cerr << "Time elapsed :" << clock() * 1000.0 / CLOCKS_PER_SEC << " ms" << '\n';
}