1def minimumFuelCost(roads, seats):
2    from collections import defaultdict
3
4    adjList = defaultdict(list)
5    visited = set()
6
7    def dfs(node):
8        visited.add(node)
9        total_rep = 1
10        for neighbor in adjList[node]:
11            if neighbor not in visited:
12                reps = dfs(neighbor)
13                nonlocal cost
14                cost += (reps + seats - 1) // seats
15                total_rep += reps
16        return total_rep
17
18    for a, b in roads:
19        adjList[a].append(b)
20        adjList[b].append(a)
21
22    cost = 0
23    dfs(0)
24    return cost
25
26roads = [[3,1],[3,2],[1,0],[0,4],[0,5],[4,6]]
27seats = 2
28print(minimumFuelCost(roads, seats))

1using System.Collections.Generic;

class Solution {
    public static long MinimumFuelCost(int[][] roads, int seats) {
        int n = roads.Length + 1;
        List<int>[] adjList = new List<int>[n];
        for (int i = 0; i < n; ++i) adjList[i] = new List<int>();
        foreach (var road in roads) {
            adjList[road[0]].Add(road[1]);
            adjList[road[1]].Add(road[0]);
        }

        bool[] visited = new bool[n];
        Queue<(int node, int reps)> q = new Queue<(int, int)>();
        q.Enqueue((0, 0));
        visited[0] = true;
        long cost = 0;

        while (q.Count > 0) {
            var (node, reps) = q.Dequeue();
            int max_reps = reps + 1;
            long nodeFuel = (max_reps + seats - 1) / seats;
            cost += nodeFuel;
            foreach (int neighbor in adjList[node]) {
                if (!visited[neighbor]) {
                    visited[neighbor] = true;
                    q.Enqueue((neighbor, max_reps));
                }
            }
        }

        return cost;
    }

    static void Main() {
        int[][] roads = { new int[]{0,1}, new int[]{0,2}, new int[]{0,3} };
        int seats = 5;
        Console.WriteLine(MinimumFuelCost(roads, seats));
    }
}