Submission #3907507

---

Source Code Expand

#include <bits/stdc++.h>
using namespace std;

#define max(a,b) ((a)>(b)?(a):(b))
#define min(a,b) ((a)<(b)?(a):(b))
#define abs(a) max((a),-(a))
#define rep(i,n) for(int i=0;i<(int)(n);i++)
#define repe(i,n) rep(i,(n)+1)
#define per(i,n) for(int i=(int)(n)-1;i>=0;i--)
#define pere(i,n) rep(i,(n)+1)
#define all(x) (x).begin(),(x).end()
#define SP <<" "<<
#define RET return 0
#define MOD 1000000007
#define INF 1000000000000000000

typedef long long LL;
typedef long double LD;

vector<int> uf;

int root(int x){
  if(x==uf[x]) return x;
  else return uf[x]=root(uf[x]);
}

void uni(int x,int y){
  x=root(x);
  y=root(y);
  if(x!=y) uf[x]=y;
}

int main(){
  int n,m;
  cin >> n >> m;
  uf=vector<int>(n);
  for(int i=0;i<n;i++){
    uf[i]=i;
  }
  vector<list<int>> l(m);
  int k,ll;
  for(int i=0;i<n;i++){
    cin >> k;
    for(int j=0;j<k;j++){
      cin >> ll;
      l[ll-1].push_back(i);
    }
  }
  int rr;
  for(int i=0;i<m;i++){
    rr=l[i].front();
    for(auto it:l[i]){
      uni(rr,it);
    }
  }
  int r=root(0);
  for(int i=0;i<n;i++){
    if(root(i)!=r){
      cout << "NO" << endl;
      return 0;
    }
  }
  cout << "YES" << endl;
  return 0;
}

Submission Info

Judge Result