只能 60 分,第二个和第四个点 WA

#include <cstring>
#include <iostream>
#include <queue>
#include <vector>
using namespace std;

void pre() {
#ifndef ONLINE_JUDGE
    freopen("in.txt", "r", stdin);
    // freopen("out.txt", "w", stdout);
#define DEBUG(A) cout << A << endl
#else
#define DEBUG(A)
#endif
}
#define N 1001000
struct edge {
    int nxt;
    int v, fl;
};
vector<edge> g;
int head[N];
int tot = 0;
inline void adde(int u, int v, int fl) {
    g.push_back({ head[u], v, fl });
    head[u] = tot++;
}
int dep[N];
bool bfs(int s, int t) {
    memset(dep, 0, sizeof(dep));
    queue<int> q;
    q.push(s);
    dep[s] = 1;
    while (q.size()) {
        int u = q.front();
        q.pop();
        for (int i = head[u]; i != -1; i = g[i].nxt) {
            // DEBUG("nxt");
            int v = g[i].v;
            int fl = g[i].fl;
            if (fl != 0 && dep[v] == 0) {
                dep[v] = dep[u] + 1;
                q.push(v);
            }
        }
    }
    return dep[t] != 0;
}
int dfs(int u, int in, int t) {
    if (u == t) {
        return in;
    }
    int out = 0;
    for (int i = head[u]; i != -1 && in != 0; i = g[i].nxt) {
        int v = g[i].v;
        int fl = g[i].fl;
        if (dep[v] == dep[u] + 1 && fl != 0) {
            int res = dfs(v, min(in, fl), t);
            in -= res;
            out += res;
            fl -= res;
            g[i].fl -= res;
            g[i ^ 1].fl += res;
        }
    }
    if (out == 0) {
        dep[u] = 0;
    }
    return out;
}
int dinic(int s, int t) {
    int ret = 0;
    while (bfs(s, t)) {
        DEBUG("bfs");
        ret += dfs(s, 0x3f3f3f3f, t);
    }
    return ret;
}
signed main() {
    pre();
    /*code here*/
    int T;
    cin >> T;
    while (T--) {
        memset(head, -1, sizeof(head));
        tot = 0;
        g.clear();
        int m, n;
        cin >> m >> n;
        int s = n + m + 1;
        int t = n + m + 2;
        for (int i = 1; i <= m; i++) {
            adde(s, i, 1);
            adde(i, s, 0);
        }
        for (int i = 1; i <= n; i++) {
            int k;
            cin >> k;
            for (int j = 1; j <= k; j++) {
                int u;
                cin >> u;
                adde(u, i + m, 1);
                adde(i + m, u, 0);
            }
        }
        for (int i = 1; i <= n; i++) {
            adde(i + m, t, 1);
            adde(t, i + m, 0);
        }
        DEBUG("ok");
        int ans = dinic(s, t);
        if (ans >= n) {
            cout << "YES" << endl;
        } else {
            cout << "NO" << endl;
        }
    }
    return 0;
}