Submission #5379531

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Source Code Expand

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
#define REP(i, n) for(int i=0; i<n; i++)
template<class T>bool chmax(T &a, const T &b) { if (a<b) { a=b; return 1; } return 0; }
template<class T>bool chmin(T &a, const T &b) { if (b<a) { a=b; return 1; } return 0; }
const ll MOD = 1e9+7;

vector<int> G[100100];
vector<int> L[100100];
bool isvisit[100100];

void dfs(int v, int x){
    isvisit[v] = true;
    for(auto l : L[v]){
        if(l == x) continue;
        for(auto next : G[l]) {
            if(isvisit[next]) continue;
            dfs(next, l);
        }
    }
}

int main(){
    int N, M;
    cin >> N >> M;
    REP(i,N){
        int K;
        cin >> K;
        REP(j,K){
            int l;
            cin >> l;
            l--;
            L[i].push_back(l);
            G[l].push_back(i);
        }
    }

    dfs(0, -1);

    bool ans = true;
    REP(i,N){
        if(!isvisit[i])
            ans = false;
    }

    if(ans)
        cout << "YES" << endl;
    else 
        cout << "NO" << endl;
    return 0;
}

Submission Info

Judge Result