1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 using namespace std;
 5
 6 const int maxn = 300 + 5;
 7 bool vis[maxn];
 8 int map[maxn][maxn], match[maxn];
 9 int N, P, cnt;
10
11 int dfs(int x)
12 {
13     for (int i = 1; i <= N; i++)   // 为p个课程找匹配,N个学生是候选人
14     {
15         if (!vis[i] && map[x][i])
16         {
17             vis[i] = 1;
18             if (!match[i] || dfs(match[i]))
19             {
20                 match[i] = x;
21       //          printf("match[%d] = %d\n", i, match[i]);
22                 return 1;
23             }
24         }
25     }
26     return 0;
27 }
28
29 void Hungary()
30 {
31     cnt = 0;
32     for (int i = 1; i <= P; i++)  // 不是N，要区分清楚！！
33     {
34         memset(vis, 0, sizeof(vis));
35         cnt += dfs(i);
36     }
37 }
38
39 int main()
40 {
41     int T, stu_num, stu_id;
42     while (scanf("%d", &T) != EOF)
43     {
44         while (T--)
45         {
46             memset(match, 0, sizeof(match));
47             memset(map, 0, sizeof(map));
48
49             scanf("%d%d", &P, &N);
50             for (int i = 1; i <= P; i++)
51             {
52                 scanf("%d", &stu_num);
53                 for (int j = 0; j < stu_num; j++)
54                 {
55                     scanf("%d", &stu_id);
56                     map[i][stu_id] = 1;
57                 }
58             }
59             Hungary();
60             printf("%s\n", cnt == P ? "YES" : "NO");
61         }
62     }
63     return 0;
64 }