hdu1068最大独立集

一开始为建图纠结了半天，后来看了解题报告才突然明白，直接按输入建成的图，其最大匹配数为实际的图的2倍。。。

/*

 * hdu1068/win.cpp

 * Created on: 2012-8-15

 * Author    : ben

 */

#include <cstdio>

#include <cstdlib>

#include <cstring>

#include <cmath>

#include <ctime>

#include <iostream>

#include <algorithm>

#include <queue>

#include <set>

#include <map>

#include <stack>

#include <string>

#include <vector>

#include <deque>

#include <list>

#include <functional>

#include <numeric>

#include <cctype>

using namespace std;

const int MAXN = 555;

vector<int> mymap[MAXN];

int N, M, mymatch[MAXN];

bool visited[MAXN];

void init() {

    for(int i = 0; i < N; i++) {

        mymap[i].clear();

    }

}

bool dfs(int k) {

    int t, I;

    for(int i = 0, size = mymap[k].size(); i < size; i++) {

        I = mymap[k][i];

        if(!visited[I]) {

            visited[I] = true;

            t = mymatch[I];

            mymatch[I] = k;

            if(t == -1 || dfs(t)) {

                return true;

            }

            mymatch[I] = t;

        }

    }

    return false;

}

int hungary () {

    memset(mymatch, -1, sizeof(mymatch));

    int ans = 0;

    for (int i = 0; i < N; i++) {

        memset(visited, false, sizeof(visited));

        if (dfs(i)) {

            ans++;

        }

    }

    return ans;

}

inline bool mypushback(vector<int> &v, int a) {

    for(int i = 0, size = v.size(); i < size; i++) {

        if(v[i] == a) {

            return false;

        }

    }

    v.push_back(a);

    return true;

}

bool buildgraph() {

    int t, k;

    if(scanf("%d", &N) == EOF) {

        return false;

    }

    init();

    for (int i = 0; i < N; i++) {

        scanf("%d: (%d)", &t, &k);

        for(int j = 0; j < k; j++) {

            scanf("%d", &t);

            mymap[i].push_back(t);

        }

    }

    return true;

}

int main() {

#ifndef ONLINE_JUDGE

    freopen("data.in", "r", stdin);

#endif

    while(buildgraph()) {

        printf("%d\n", N - hungary() / 2);

    }

    return 0;

}