POJ 1469 COURSES【二分图最大匹配】

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <vector>
 5 using namespace std;
 6 
 7 const int maxn = 305;
 8 
 9 int n;
10 
11 vector<int> G[maxn];
12 int vis[maxn];
13 int Link[maxn];
14 bool Find(int u) {
15     for(int i = 0;i < G[u].size(); i++) {
16         int v = G[u][i];
17         if(!vis[v]) {
18             vis[v] = 1;
19             if(Link[v] == -1 || Find(Link[v]) ) {
20                 Link[v] = u;
21                 return true;
22             }
23         }
24     }
25     return false;
26 }
27 
28 int solve() {
29     int cnt = 0;
30     memset(Link, -1, sizeof(Link));
31     for(int i = 1; i <= n; i++) {
32         memset(vis, 0, sizeof(vis));
33         if(Find(i)) cnt++;
34     }
35     return cnt;
36 }
37 int main() {
38     int t;
39     int p;
40     int num, _num;
41     scanf("%d",&t);
42     while(t--) {
43         scanf("%d %d",&n, &p);
44         for(int i = 0; i <= n; i++) {
45             G[i].clear();
46         }
47         for(int i = 1; i <= n; i++) {
48             scanf("%d",&num);
49             for(int j = 0; j < num; j++) {
50                 scanf("%d",&_num);
51                 G[i].push_back(_num);
52             }
53         }
54         if(solve() == n) puts("YES");
55         else puts("NO");
56     }
57     return 0;
58 }