Submission #1678185

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Source Code Expand

#include <algorithm>
#include <iostream>
#include <set>
#include <vector>
#include <utility>
#include <queue>
using namespace std;
int main(){
  int N, M;
  cin >> N >> M;
  vector< vector<int> > L(M), V(N);
  int k;
  for(int i = 0; i < N; ++i){
    cin >> k;
    vector<int> t;
    int l;
    for(int j = 0; j < k; ++j){
      cin >> l;
      --l;
      L[l].push_back(i);
      t.push_back(l);
    }
    V[i] = t;
  }
  bool T[N], Useable[M];
  fill(T,T+N,false);
  fill(Useable,Useable+M,false);
  T[0] = true;
  queue<int> que;
  que.push(0);
  while(!que.empty()){
    int t = que.front();
    que.pop();
    for(int i = 0; i < V[t].size(); ++i){
      int l = V[t][i];
      if(!Useable[l]){
	Useable[l] = true;
	for(int j = 0; j < L[l].size(); ++j){
	  if(!T[L[l][j]]){
	    T[L[l][j]] = true;
	    que.push(L[l][j]);
	  }
	}
      }
    }
  }
  bool f = true;
  for(int i = 0; i < N; ++i){
    if(!T[i]){
      f = false;
      break;
    }
  }
  if(f) cout << "YES" << endl;
  else cout << "NO" << endl;
  return 0;
}

Submission Info

Judge Result