Submission #992057

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Source Code Expand

#include<bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef pair<int,int> pii;
typedef pair<pii,int> piii;
typedef pair<ll,ll> pll;

#define reps(i,f,n) for(int i = int(f); i <= int(n); i++)
#define rep(i,n) reps(i,0,int(n)-1)
#define rrep(i,n) for(int i = n-1; i >= 0; i--)

#define all(x) (x).begin(),(x).end()
#define X first
#define Y second

#define sz size()
#define eb emplace_back
#define pb push_back

vector<int> x[100001];
int used[100001];
int ok[100001];



int main(void){
  int n, m, k, l;
  
  queue<int> q;
  cin >> n >> m;
  rep(i,n){
    cin >> k;
    vector<int> tmp;
    rep(j,k){
      cin >> l;
      tmp.push_back(l);
    }
    rep(j,k){
      used[tmp[j]] = 1;
      rep(ij,j){
        x[tmp[j]].push_back(tmp[ij]);
        x[tmp[ij]].push_back(tmp[j]);
      }
    }
  }
  q.push(l);
  while(!q.empty()){
    int tp = q.front();q.pop();
    rep(i,x[tp].size()){
      if(!ok[x[tp][i]]){
        ok[x[tp][i]] = 1;
        q.push(x[tp][i]);
      }
    }
  }

  rep(i,m){
    if(ok[i] != used[i]){
      cout << "NO" << endl;
      return 0;
    }
  }

  cout << "YES" << endl;
  
  return 0;
}

Submission Info

Judge Result