HDU - 1083 Courses （二分图最大匹配模板）

#include <cstdio>
#include <iostream>
#include <algorithm>
#include <cstring>
using namespace std;
const int maxn = 1e3;
const int maxm = 1e6;
int match[maxn];
int vis[maxn];
int head[maxn]; 
int top,ans;
int n,m;
struct Edge
{
    int v,next;
}edge[maxm];
void add(int u,int v){
    edge[top].v = v;
    edge[top].next = head[u];
    head[u] = top++;
}
void init(){
    memset(head,-1,sizeof(head));
    memset(match,0,sizeof(match));
    top = ans = 0;
}
//匈牙利算法：递归找增广路径
bool Find(int u){
    for(int i = head[u]; ~i ;i =edge[i].next){
        int v = edge[i].v;
        if(!vis[v]){
            vis[v] = 1;
            if(!match[v]||Find(match[v])){
                match[v] = u;
                return true;
            }
        }
    }
    return false;
}
int main(){
    int T;
    cin>>T;
    while(T--){
        cin>>n>>m;
        int num;
        init();
        for(int i = 1;i<=n;i++){
            cin>>num;
            while(num--){
                int v;
                cin>>v;
                add(i,v);
            }
        }
        for(int i = 1;i<=n;i++){
            memset(vis,0,sizeof(vis));
            if(Find(i)) ans++;
        }
        if(ans==n) cout<<"YES"<<endl;
        else cout<<"NO"<<endl;
    }
}