HDU 1068 — Girls and Boys 最大独立集

#include<stdio.h>
#include<vector>
#include<string.h>
#include<iostream>
#include<algorithm>

using namespace std;
const int maxn = 1500;
int lef[maxn];
bool T[maxn];
int n;
vector<int>G[maxn];
bool match(int x)  
{  
    for(int i = 0;i<G[x].size();i++)  
    {  
        int v = G[x][i];  
        if(!T[v])  
        {  
            T[v] = true;  
            if(lef[v] == -1 || match( lef[v] ))  
            {  
                lef[v] = x;  
                return true;  
            }  
        }  
    }  
    return false;  
}  
  
int solve()  
{  
    memset(lef, -1, sizeof(lef));  
    int ans = 0;  
    for(int i = 0;i<n;i++)  
    {     
        memset(T, 0, sizeof(T));  
        if( match(i) )   
        ans++;  
    }  
    return ans;  
} 

int main()
{
    while(scanf("%d", &n)!=EOF)
    {
        int m, k;
        for(int i = 0;i<n;i++)
        G[i].clear();
        for(int i = 0;i<n;i++)
        {
            scanf("%d: (%d)", &m, &k);
            for(int j = 0;j<k;j++)
            {
                int x;
                scanf("%d", &x);
                G[i].push_back(x);
            }
        }
		int ans = solve();
        printf("%d\n", n-ans/2);
    }    
    return 0;
}