poj1422最大独立点集合

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <climits>
#include <string>
#include <iostream>
#include <map>
#include <cstdlib>
#include <list>
#include <set>
#include <queue>
#include <stack>
#include<math.h>
using namespace std;
const int maxn=222;
int Map[maxn][maxn];
int link[maxn];
int used[maxn];
int n;
int dfs(int x)
{
    for(int i=1;i<=n;i++){
        if(!used[i]&&Map[x][i]){
            used[i]=1;
            if(link[i]==-1||dfs(link[i])){
                link[i]=x;return 1;
            }
        }
    }
    return 0;
}

void gao()
{
    memset(link,-1,sizeof(link));
    int ans=0;
    for(int i=1;i<=n;i++){
        memset(used,0,sizeof(used));
        if(dfs(i)) ans++;
    }
    cout<<n-ans<<endl;
}
int main()
{
    int Icase;
    int m;
    scanf("%d",&Icase);
    while(Icase--){
        scanf("%d",&n);
        scanf("%d",&m);
        memset(Map,0,sizeof(Map));
        for(int i=0;i<m;i++){
            int a;int b;
            scanf("%d%d",&a,&b);
            Map[a][b]=1;
        }
        gao();
    }
    return 0;
}