Submission #991874

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Source Code Expand

#include <algorithm>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <ctime>
#include <iostream>
#include <sstream>
#include <functional>
#include <map>
#include <string>
#include <cstring>
#include <vector>
#include <queue>
#include <stack>
#include <deque>
#include <set>
#include <list>
#include <numeric>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll> P;
const double PI = 3.14159265358979323846;
const double EPS = 1e-12;
const ll INF = 1LL<<29;
const ll mod = 1e9+7;
#define rep(i,n) for(int (i)=0;(i)<(ll)(n);++(i))
#define repd(i,n,d) for(ll (i)=0;(i)<(ll)(n);(i)+=(d))
#define all(v) (v).begin(), (v).end()
#define pb(x) push_back(x)
#define mp(x,y) make_pair((x),(y))
#define mset(m,v) memset((m),(v),sizeof(m))
#define chmin(X,Y) ((X)>(Y)?X=(Y),true:false)
#define chmax(X,Y) ((X)<(Y)?X=(Y),true:false)
#define fst first
#define snd second
#define UNIQUE(x) (x).erase(unique(all(x)),(x).end())
template<class T> ostream &operator<<(ostream &os, const vector<T> &v){int n=v.size();rep(i,n)os<<v[i]<<(i==n-1?"":" ");return os;}

#define MAX_N 200000

struct UF {
	int par[MAX_N],rank[MAX_N];
	
	void init(int n){
		for(int i = 0; i < n; i++){
			par[i] = i;
			rank[i] = 0;
		}
	}
	
	int find(int x){
		if(par[x] == x){
			return x;
		}else{
			return par[x] = find(par[x]);
		}
	}
	
	void unite(int x, int y){
		x = find(x);
		y = find(y);
		if(x == y) return;
		
		if(rank[x] < rank[y]){
			par[x] = y;
		}else{
			par[y] = par[x];
			if(rank[x] == rank[y]) rank[y]++;
		}
	}
	
	bool same(int x, int y){
		return find(x) == find(y);
	}
};

int n, m;
int l[MAX_N];
int main(){
	mset(l, -1);
	cin>>n>>m;
	UF uf;
	uf.init(n);
	rep(i, n){
		int k;
		cin>>k;
		rep(j, k){
			int t;
			cin>>t;
			if(l[t]<0) l[t] = i;
			else uf.unite(l[t], i);
		}
	}
	bool ok = true;
	rep(i, n) if(!uf.same(0, i)) ok = false;
	cout<<(ok?"YES":"NO")<<endl;
	return 0;
}

Submission Info

Judge Result