Submission #995859

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Source Code Expand

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

#define rep(i,n) for(int i=0;i<n;i++)
#define reps(i,m,n) for(int i=m;i<n;i++)

typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int uint;
typedef vector<int> vec;
typedef vector<vec> mat;
static const double EPS = 1e-9;
static const double PI = acos(-1.0);
const int INF = 1e9;
const int mod = 1e9 + 7;
const int MAX = 200005;

vector<int> g[MAX];
bool used[MAX] = {0};

int N, M;

void is_connected(int v) {
    if(used[v]) return;
    used[v] = true;
    for(int i=0;i<g[v].size();++i) {
        is_connected(g[v][i]);
    }
}
int main(){
    cin >> N >> M;
    for(int i=0;i<N;++i) {
        int k;
        cin >> k;
        int l;
        for(int j=0;j<k;++j)  {
            cin >> l;
            g[i].push_back(N+l);
            g[N+l].push_back(i);
        }
    }

    is_connected(0);
    for(int i=0;i<N;++i) {
        if(used[i] == false)  {
            cout << "NO" << endl;
            return 0;
        }
    }
    cout << "YES" << endl;
    return 0;
}

Submission Info

Judge Result