hdu

http://acm.hdu.edu.cn/showproblem.php?pid=1068

因为没有指定性别,所以要拆点,把i拆分i和i’ 那么U=V-M (M是最大匹配,U最大独立集,V是顶点数) 

2U=2V-2M  所以 U=n-M'/2. (没怎么看明白)  但是不这样会wa.

#include <iostream>
#include <cstdio>
#include <cmath>
#include <vector>
#include <cstring>
#include <string>
#include <algorithm>
#include <string>
#include <set>
#include <functional>
#include <numeric>
#include <sstream>
#include <stack>
#include <map>
#include <queue>
#pragma comment(linker, "/STACK:102400000,102400000")
#define CL(arr, val)    memset(arr, val, sizeof(arr))

#define ll long long
#define inf 0x7f7f7f7f
#define lc l,m,rt<<1
#define rc m + 1,r,rt<<1|1
#define pi acos(-1.0)

#define L(x)    (x) << 1
#define R(x)    (x) << 1 | 1
#define MID(l, r)   (l + r) >> 1
#define Min(x, y)   (x) < (y) ? (x) : (y)
#define Max(x, y)   (x) < (y) ? (y) : (x)
#define E(x)        (1 << (x))
#define iabs(x)     (x) < 0 ? -(x) : (x)
#define OUT(x)  printf("%I64d
", x)
#define lowbit(x)   (x)&(-x)
#define Read()  freopen("a.txt", "r", stdin)
#define Write() freopen("b.txt", "w", stdout);
#define maxn 1000000000
#define N 510
#define mod 1000000000
using namespace std;

vector<int>G[N];
int link[N];
bool vis[N];

bool dfs(int u)
{
    for(int i=0;i<G[u].size();i++)
    {
        int v=G[u][i];
        if(!vis[v])
        {
            vis[v]=true;
            if(link[v]==-1||dfs(link[v]))
            {
                link[v]=u;
                return true;
            }
        }
    }
    return false;
}
int main()
{
    //Read();
    int n,a,b,c;
    while(~scanf("%d",&n))
    {
        for(int i=0;i<n;i++) G[i].clear();
        for(int i=0;i<n;i++)
        {
            scanf("%d: (%d)",&a,&b);
           // printf("%d %d
",a,b);
            for(int i=0;i<b;i++)
            {
                scanf("%d",&c);
                G[a].push_back(c);
            }
        }
        int ans=0;
        memset(link,-1,sizeof(link));
        for(int i=0;i<n;i++)
        {
            memset(vis,0,sizeof(vis));
            if(dfs(i)) ans++;
        }
        printf("%d
",n-ans/2);
    }
    return 0;
}