COURSES
1 #include <iostream>
2 #include <cstdio>
3 #include <cstring>
4 #include <cmath>
5 #include <algorithm>
6 #include <string>
7 #include <vector>
8 #include <set>
9 #include <map>
10 #include <stack>
11 #include <queue>
12 #include <sstream>
13 #include <iomanip>
14 using namespace std;
15 typedef long long LL;
16 const int INF = 0x4fffffff;
17 const double EXP = 1e-5;
18 const int MS = 305;
19 const int SIZE = 100005;
20
21 // data struct
22 int n,m;
23 int edges[MS][MS];
24 int cx[MS],cy[MS];
25 int mark[MS];
26
27 int path(int u)
28 {
29 for(int v=1;v<=m;v++)
30 {
31 if(edges[u][v]&&!mark[v])
32 {
33 mark[v]=1;
34 if(cy[v]==-1||path(cy[v]))
35 {
36 cx[u]=v; // 可以不要cx
37 cy[v]=u;
38 return 1;
39 }
40 }
41 }
42 return 0;
43 }
44
45 void match()
46 {
47 int ans=0;
48 memset(cx,0xff,sizeof(cx));
49 memset(cy,0xff,sizeof(cy));
50 for(int u=1;u<=n;u++)
51 {
52 if(cx[u]==-1)
53 {
54 memset(mark,0,sizeof(mark));
55 ans+=path(u);
56 }
57 }
58 if(ans==n)
59 printf("YES\n");
60 else
61 printf("NO\n");
62 }
63
64 int main()
65 {
66 int T,u,v;
67 scanf("%d",&T);
68 while(T--)
69 {
70 scanf("%d%d",&n,&m);
71 memset(edges,0,sizeof(edges));
72 int cnt;
73 for( u=1;u<=n;u++)
74 {
75 scanf("%d",&cnt);
76 for(int i=1;i<=cnt;i++)
77 {
78 scanf("%d",&v);
79 edges[u][v]=1;
80 }
81 }
82 match();
83
84 }
85 return 0;
86 }
