Submission #1357257

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Source Code Expand

#include <iostream>
#include <fstream>
#include <vector>
using namespace std;

vector<int> result;
int used[2 * 100000 + 10];
int este[100000 + 10];

vector<vector<int>> edges(2 * 100000 + 10);
void dfs(int node) {
    used[node] = 1;
    result.push_back(node);
    for(int son : edges[node]) {
        if(!used[son]) {
            dfs(son);
        }
    }
}

int main() {
    int n, m;
    cin >> n >> m;
    for(int i = 0; i < n; i++) {
        int k;
        cin >> k;
        for(int j = 0; j < k; j++) {
            int x;
            cin >> x;
            edges[x].push_back(m + i + 1);
            edges[m + i + 1].push_back(x);
        }
    }
    dfs(m + 1);
    for(int i = 0; i < result.size(); i++) {
        if(result[i] > m) {
            este[result[i] - m] = 1;
        }
    }
    bool ok = true;
    for(int i = 1; i <= n; i++) {
        if(este[i] == 0) {
            ok = false;
        }
    }
    ok ? cout << "YES" : cout << "NO";
    return 0;
}

Submission Info

Judge Result