Submission #5017520

---

Source Code Expand

#include <bits/stdc++.h>
using namespace std;
int fa[100005];
int find(int x){
   return x==fa[x]?fa[x]:fa[x]=find(fa[x]);
}
void combine(int x,int y){
   int f1=find(x);
   int f2=find(y);
   if(f1!=f2)fa[f1]=f2;
}
int n,m;
vector<int>vec[100005];
int vis[100005];
int main(){
    cin>>n>>m;
    for(int i=1;i<=n;i++)
        fa[i]=i;
    for(int i=1;i<=n;i++){
      int k;
      cin>>k;
      for(int j=1;j<=k;j++){
        int x;
        cin>>x;
        vis[x]=1;
        vec[x].push_back(i);
      }
    }
    for(int i=1;i<=m;i++){
      for(int j=1;j<vec[i].size();j++){
        combine(vec[i][0],vec[i][j]);
      }
    }
    int sum=0;
    for(int i=1;i<=n;i++){
        if(fa[i]==i) {sum++;}
    }
   // cout<<sum<<"\n";
    if(sum==1)cout<<"YES\n";
    else cout<<"NO\n";
}

Submission Info

Judge Result