Submission #1857019

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Source Code Expand

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



void dfs(vector<bool>& used, vector<vector<bool> >& graph, int c, int n, int m){
    
    if(used[c]) return;
    used[c] = true;
    for(int i = 1; i <= n + m; i++){
        if(graph[c][i]){
            dfs(used, graph, i, n, m);
        }
    }
}

int main(void){

    int n, m; cin >> n >> m;
    vector<vector<bool> > graph(n + m + 1, vector<bool> (n + m + 1, false));

    for(int i = 1; i <= n; i++){
        int k; cin >> k;
        for(int j = 0; j < k; j++){
            int l; cin >> l;
            graph[i][n + l] = graph[n + l][i] = true;
        }
    }
    
    vector<bool> used(n + m + 1, false);
    dfs(used, graph, 1, n, m);

    bool flag = true;
    for(int i = 1; i <= n; i++){
        if(used[i] == false){
            flag = false;
            break;
        }
    }

    if(flag) cout << "YES" << endl;
    else cout << "NO" << endl;

    return 0;
}

Submission Info

Judge Result