Code Room
CodingMediumcod-g015
Subject GraphsLevel Mid–Senior~30 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

An undirected graph is given as an adjacency list: adj[i] is the list of neighbor indices of node i (0..n-1). Produce a deep clone and return its adjacency list, but with node indices remapped to a canonical order: perform a BFS from node 0 and assign new ids 0,1,2,... in the order nodes are first discovered (neighbors explored in ascending original-index order). Return the cloned graph's adjacency list under the new ids, with each neighbor list sorted ascending. If n is 0 return an empty list. The graph may be disconnected; nodes unreachable from 0 are appended afterward in ascending original-index order.

Implement
clone_relabel(adj: list[list[int]]) → list[list[int]]
Examples
in[[[1,2],[0,2],[0,1]]]out[[1,2],[0,2],[0,1]]
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.

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.