Submission #991886

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Source Code Expand

#include <algorithm>
#include <cassert>
#include <cctype>
#include <cstdlib>
#include <cmath>
#include <cstdio>
#include <functional>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#include <utility>

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

using namespace std;

typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int, int> pii;

const int INF = 1001001001;

vector<bool> visited;
vvi G;

void dfs(int v)
{
    visited[v] = true;
    for(int u : G[v]){
        if(!visited[u]){
            dfs(u);
        }
    }
}

signed main()
{
    int n, m;
    cin >> n >> m;
    G.resize(m);
    
    vi appear;
    
    rep(i, n){
        int k;
        cin >> k;
        vi lang(k);
        rep(j, k){
            cin >> lang[j];
            lang[j]--;
            appear.push_back(lang[j]);
        }
        rep(j, k-1){
            int a = lang[j];
            int b = lang[j+1];
            G[a].push_back(b);
            G[b].push_back(a);
        }
    }
    
    visited.assign(m, false);
    dfs(0);
    
    for(int l : appear){
        if(!visited[l]){
            cout << "NO" << endl;
            return 0;
        }
    }
    
    cout << "YES" << endl;
}

Submission Info

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