Code Room
CodingHard
Question
Given a tree with n nodes (0..n-1) described by an edge list, return an array res where res[v] is the sum of distances from node v to every other node. Use rerooting (two DFS passes) so the whole answer is computed in O(n). Constraints: 1 <= n <= 30000; the input is a connected undirected tree given as n and a list of [u, v] edges.
Implement
sum_of_distances(n: int, edges: list[list[int]]) → list[int]Examples
in
[6,[[0,1],[0,2],[2,3],[2,4],[2,5]]]out[8,12,6,10,10,10]What a strong answer looks like
State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.
Learn the concepts
Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.
Run or narrate your approach, then ask the coach.