HDU 1054 Strategic Game

http://acm.hdu.edu.cn/showproblem.php?pid=1054

#include <cstdio>
#include <cstring>
using namespace std;

const int N=1510,M=3010;
struct edge
{
    int v,next;
}e[M];
int head[N],n,m;
bool vis[N];
int mat[N];
void graphinit()
{
    memset(head,-1,sizeof(head));
    m=0;
}
void addedge(int u,int v)
{
    edge et={v,head[u]};
    e[m]=et;
    head[u]=m++;
}
bool read_graph()
{
    graphinit();
    if(scanf("%d",&n)==EOF) return false;
    for(int i=0;i<n;i++)
    {
        int u,c;
        scanf("%d:(%d)",&u,&c);
        while(c--)
        {
            int v;
            scanf("%d",&v);
            addedge(u,v);
            addedge(v,u);
        }
    }
    return true;
}
bool find(int u)
{
    for(int i=head[u];i!=-1;i=e[i].next)
    {
        int v=e[i].v;
        if(vis[v]) continue;
        vis[v]=true;
        if(mat[v]==-1 || find(mat[v]))
        {
            mat[v]=u;
            return true;
        }
    }
    return false;
}
int maxmatch()
{
    int cnt=0;
    memset(mat,-1,sizeof(mat));
    for(int i=0;i<n;i++)
    {
        memset(vis,0,sizeof(vis));
        if(find(i)) cnt++;
    }
    return cnt;
}
int main()
{
    while(read_graph())
    {
        int ans=maxmatch()/2;
        printf("%d\n",ans);
    }
    return 0;
}