Submission #992613

---

Source Code Expand

#include <bits/stdc++.h>

using namespace std;

#define REP(i,a,b) for(int i=a;i<(int)b;i++)
#define rep(i,n) REP(i,0,n)
#define all(c) (c).begin(), (c).end()
#define zero(a) memset(a, 0, sizeof a)
#define minus(a) memset(a, -1, sizeof a)
#define watch(a) { cout << #a << " = " << a << endl; }
template<class T1, class T2> inline bool minimize(T1 &a, T2 b) { return b < a && (a = b, 1); }
template<class T1, class T2> inline bool maximize(T1 &a, T2 b) { return a < b && (a = b, 1); }

typedef long long ll;
int const inf = 1<<29;

int main() {

  int N, M; cin >> N >> M;
  vector<vector<int>> G(N);
  rep(i, N) {
    int K; cin >> K;
    rep(i, K) {
      int l; cin >> l;
      G[i].push_back(l - 1);
    }
  }

  queue<int> q;
  q.push(0);

  vector<int> dist(N, inf);

  while(!q.empty()) {
    auto p = q.front(); q.pop();
    for(auto e: G[p]) {
      if(dist[e] == inf) {
        dist[e] = dist[p] + 1;
        q.push(e);
      }
    }
  }

  bool ok = 1;
  rep(i, N) {
    ok &= dist[i] != inf;
  }

  cout << (ok ? "YES" : "NO") << endl;
  
  return 0;
}

Submission Info

Judge Result