POJ 1469 COURSES

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cmath>
 5 #include <algorithm>
 6 #include <climits>
 7 #include <vector>
 8 #include <queue>
 9 #include <cstdlib>
10 #include <string>
11 #include <set>
12 #define LL long long
13 #define INF 0x3f3f3f3f
14 using namespace std;
15 const int maxn = 310;
16 int mp[maxn][maxn],p,n;
17 int link[maxn];
18 bool used[maxn];
19 bool dfs(int u){
20     for(int i = 1; i <= n; i++){
21         if(mp[u][i] && !used[i]){
22             used[i] = true;
23             if(link[i] == -1 || dfs(link[i])){
24                 link[i] = u;
25                 return true;
26             }
27         }
28     }
29     return false;
30 }
31 int main(){
32     int t,temp,i,j;
33     scanf("%d",&t);
34     while(t--){
35         scanf("%d%d",&p,&n);
36         memset(mp,0,sizeof(mp));
37         for(i = 1; i <= p; i++){
38             scanf("%d",&j);
39             while(j--){
40                 scanf("%d",&temp);
41                 mp[i][temp] = 1;
42             }
43         }
44         int ans = 0;
45         memset(link,-1,sizeof(link));
46         for(i = 1; i <= p; i++){
47             memset(used,false,sizeof(used));
48             if(dfs(i)) ans++;
49         }
50         ans == p?puts("YES"):puts("NO");
51     }
52     return 0;
53 }