Submission #1865199

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Source Code Expand

#include<iostream>
#include<string>
#include<vector>
#include<utility>
#include<queue>
#include<algorithm>
#include<cmath>
#include<cstdio>
#include<cstring>
#include<cstdlib>
#include<complex>
#define INF 2147483647
#define llINF 9223372036854775807
#define pb push_back
#define mp make_pair 
#define F first
#define S second
#define ll long long

using namespace std;
class UF{
public:
  int o[200100];
  int u[200100];
  UF(int n){
    for(int i=0;i<n;i++){
      o[i]=-1;
      u[i]=i;
    }
  }

  int root(int s){
    while(o[s]>=0)
      s=o[s];
    return u[s];
  }
  
  void merge(int x, int y){
    x = root(x);
    y = root(y);
    if(x == y) return;
    o[x]+=o[y];
    o[y]=x;
  }

  bool same(int x,int y){
    return root(x) == root(y);
  }
};
int main(){
  int n,m;cin>>n>>m;
  UF uni(m+n);
  for(int i=0;i<n;i++){
    int k;cin>>k;
    for(int j=0;j<k;j++){
      int aa;cin>>aa;
      uni.merge(i,aa-1);
    }
  }
  bool flag=true;
  for(int i=0;i<n+m;i++){
    //cout<<-uni.o[i]<<endl;
    if(uni.o[i]>0){
      flag=false;break;
    }
  }
  if(flag)
    cout<<"YES"<<endl;
  else
    cout<<"NO"<<endl;
  return 0;
}

Submission Info

Judge Result