Code Room
CodingEasycod-g552
Subject Lowest common ancestorLevel Entry–Mid~20 minCommon in Algorithms & data structures interviewsIndustries Software development

Question

Given a binary search tree as a level-order array (None marks a missing child) and two values p and q that are both present, return the value of their lowest common ancestor. Exploit the BST ordering instead of a general-tree LCA: starting at the root, go left when both p and q are smaller than the current node, go right when both are larger, and otherwise the current node is the split point and therefore the LCA. Return the LCA value.

Implement
lca_bst(level: list, p: int, q: int) → int
Examples
in[[6,2,8,0,4,7,9,null,null,3,5],2,8]out6
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.