CodingMediumcod-g056

Subject Binary search treeLevel Mid–Senior~20 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given a binary search tree as a level-order array `arr` (null for missing) and an integer `target`, return the node value closest to `target`. If two values are equally close, return the smaller one. The tree is a valid, non-empty BST. `1 <= node count <= 100000`.

Implement

closest_bst_value(arr: list[int], target: int) → int

Examples

in[[4,2,5,1,3],3]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.