Submission #992201

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Source Code Expand

#include<bits/stdc++.h>

#define REP(i,s,n) for(int i=s;i<n;i++)
#define rep(i,n) REP(i,0,n)

using namespace std;

#define MAX 100010

int par[MAX];

int find(int x) {
  if( par[x] == x ) return x;
  return par[x] = find(par[x]);
}

void unit(int x,int y) {
  x = find(x), y = find(y);
  if( x != y ) par[x] = y;
}

int N,M;
deque<int> deq[MAX];

int main(){
  cin >> N >> M;
  rep(i,N) par[i] = i;
  rep(i,N) {
    int k,l;
    cin >> k;
    rep(j,k) {
      cin >> l;
      deq[l].push_back(i);
    }
  }

  rep(i,M+1) {
    REP(j,1,(int)deq[i].size()) {
      unit(deq[i][j-1],deq[i][j]);
    }
  }

  set<int> S;
  rep(i,N) {
    S.insert(find(i));
    if( (int)S.size() >= 2 ) {
      puts("NO");
      return 0;
    }
  }
  puts("YES");
  return 0;
}

Submission Info

Judge Result