HDU-1068-GirlsandBoys(最大独立集,二分图匹配)

#include <iostream>
#include <memory.h>
#include <string>
#include <istream>
#include <sstream>
#include <vector>
#include <stack>
#include <algorithm>
#include <map>
#include <queue>
#include <math.h>
#include <cstdio>
#include <set>
#include <iterator>
#include <cstring>
using namespace std;

typedef long long LL;
const int MAXN = 2000+10;
vector<int> G[MAXN];
int Link[MAXN], Vis[MAXN];
int n;

void Init()
{
    for (int i = 0;i < n;i++)
        G[i].clear();
}

bool Dfs(int x)
{
    for (int i = 0;i < G[x].size();i++)
    {
        int node = G[x][i];
        if (Vis[node])
            continue;
        Vis[node] = 1;
        if (Link[node] == -1 || Dfs(Link[node]))
        {
            Link[node] = x;
            return true;
        }
    }
    return false;
}

int Solve()
{
    int cnt = 0;
    memset(Link, -1, sizeof(Link));
    for (int i = 0;i < n;i++)
    {
        memset(Vis, 0, sizeof(Vis));
        if (Dfs(i))
            cnt++;
    }
    return cnt;
}

int main()
{
    while (~scanf("%d", &n))
    {
        Init();
        int s, num, p;
        for (int i = 0; i < n; i++)
        {
            scanf("%d: (%d)", &s, &num);
            for (int j = 1;j <= num;j++)
            {
                scanf("%d", &p);
                G[s].push_back(p);
            }
        }
        int cnt = Solve();
        printf("%d\n", n-cnt/2);
    }

    return 0;
}