void bfs(int n, vector<vector<int>>& edgelist, vector<int>& dist, queue<int>& q) {

    for (int i : edgelist[n]) {
        if (dist[i] != -1) continue;
        dist[i] = dist[n] + 1;
        q.push(i);
    }

    if (!q.empty()) {
        n = q.front();
        q.pop();
        bfs(n, edgelist, dist, q);
    }
}