二分图最大匹配模板 HDU1083

题目大意：

P个老师，N个学生，能否达到最大匹配P；

#include<bits/stdc++.h>
#define pb push_back
const int maxn = 300 + 5;
using namespace std;
int P,N;
vector<int> G[maxn];
int linker[maxn];
bool used[maxn];
bool dfs (int u) {
    int now ;
    for ( int v = 0 ; v < G[u].size() ; v ++ ){
        now = G[u][v];
        if(!used[now]){
            used[now] = true ;
            if( linker[now] == -1 || dfs(linker[now]) ){
                linker[now] = u;
                return true ;
            }
        }
    }
    return false;
}
int hungary(){
    int res = 0;
    memset( linker , -1 ,sizeof( linker ));
    for ( int u = 1; u <= P ; u++) {
         memset ( used , false ,sizeof (used )) ;
         if( dfs(u)) res ++ ;
    }
    return res ;
}
int main () {
    int T , tot , v ;
    cin >> T;
    while (T--) {
        cin >> P >> N;
        for ( int i = 1 ; i <= P ;i ++) {
            cin >> tot ;
            for ( int j = 1; j <= tot ; j++){
                cin >> v ;
                G[i].pb (v);
            }
        }
        printf ( "%s\n" ,  hungary() == P ? "YES" : "NO" );
        for ( int i = 1; i <= P ; i++ ) G[i].clear();
    }
    return 0;
}