BNUOJ 1585 Girls and Boys

 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 #include <stack>
13 #define LL long long
14 #define pii pair<int,int>
15 #define INF 0x3f3f3f3f
16 using namespace std;
17 const int maxn = 1005;
18 struct arc{
19     int to,next;
20 };
21 arc g[200100];
22 int head[maxn],from[maxn],tot,n;
23 bool vis[maxn];
24 void add(int u,int v){
25     g[tot].to = v;
26     g[tot].next = head[u];
27     head[u] = tot++;
28 }
29 bool dfs(int u){
30     for(int i = head[u]; i != -1; i = g[i].next){
31         if(!vis[g[i].to]){
32             vis[g[i].to] = true;
33             if(from[g[i].to] == -1 || dfs(from[g[i].to])){
34                 from[g[i].to] = u;
35                 return true;
36             }
37         }
38 
39     }
40     return false;
41 }
42 int main() {
43     int i,j,k,u,v,ans;
44     while(~scanf("%d",&n)){
45         memset(head,-1,sizeof(head));
46         memset(from,-1,sizeof(from));
47         tot = 0;
48         for(i = 0; i < n; i++){
49             scanf("%d: (%d)",&j,&k);
50             for(j = 0; j < k; j++){
51                 scanf("%d",&v);
52                 add(i,v);
53                 add(v,i);
54             }
55         }
56         for(ans = i = 0; i < n; i++){
57             memset(vis,false,sizeof(vis));
58             if(dfs(i)) ans++;
59         }
60         ans >>= 1;
61         printf("%d\n",n-ans);
62     }
63     return 0;
64 }