CodingMediumcod-g310

Subject Lowest common ancestorLevel Mid–Senior~30 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given a binary tree as a level-order list (None marks a missing child; children of None are omitted) and two values p and q that may or may not be present, return the number of edges on the path between the nodes with those values. All node values are distinct. If either value is absent, return -1. If p == q (and present), the distance is 0.

Implement

distance_between_nodes(level: list, p: int, q: int) → int

Examples

in[[3,5,1,6,2,0,8,null,null,7,4],5,0]out3

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.