1 #include<bits/stdc++.h>
 2 
 3 using namespace std;
 4 
 5 int n, t;
 6 bool ans;
 7 const int MAXN = 110000;
 8 int g[MAXN][15], f[MAXN], gx, w[MAXN];
 9 
10 bool add (int u, string s, int x) {
11     if (x >= s.length()) return 0;
12     w[u] = 1;
13     if (f[g[u][s[x] - ‘0‘]]) {
14         return 0;
15     }
16     else {
17         if (!g[u][s[x] - ‘0‘]) g[u][s[x] - ‘0‘] = ++gx;
18         if (x == s.length() - 1) {
19             if (w[g[u][s[x] - ‘0‘]]) return 0;
20             f[g[u][s[x] - ‘0‘]] = 1;
21             w[g[u][s[x] - ‘0‘]] = 1;
22             return 1;
23         }
24         else {
25             return add(g[u][s[x] - ‘0‘], s, x + 1);
26         }
27     }
28 }
29 
30 int main() {
31     cin >> t;
32     while (t--) {
33         ans = 1;
34         cin >> n;
35         memset(f, 0, sizeof(f));
36         memset(g, 0, sizeof(g));
37         memset(w, 0, sizeof(w));        
38         gx = 1;
39         while (n--) {
40             string s;
41             cin >> s;
42             ans = min(ans, add(1, s, 0));
43         }
44         if (ans) {
45             cout << "YES\n";
46         }
47         else {
48             cout << "NO\n";
49         }
50     }
51     return 0;
52 }

 1 #include<bits/stdc++.h>
 2 
 3 using namespace std;
 4 
 5 string s[10001];
 6 
 7 int main() {
 8     int t;
 9     cin >> t;
10     while (t--) {
11         int n;
12         cin >> n;
13         for (int i = 1; i <= n; ++i) cin >> s[i];
14         sort(s + 1, s + 1 + n);
15         bool tf = 1;
16         for (int i = 2; i <= n && tf; ++i) {
17             if (s[i].length() > s[i - 1].length()) {
18                 bool x = 1;
19                 for (int j = 0; j < s[i - 1].length(); ++j) {
20                     if (s[i - 1][j] != s[i][j]) {
21                         x = 0;
22                         break;
23                     }
24                 }
25                 if (x) tf = 0;
26             }
27         }
28         if (tf) cout << "YES\n";
29         else cout << "NO\n";
30     }
31     return 0; 
32 }