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Meta·Software Engineer·Onsite - Coding / Algorithms·Intermediate

IntermediatePrefer not to say
Jun 2026Remote

Summary

Meta virtual onsite coding round, got a tree traversal problem that was close to a well-known leetcode but with a twist thrown in. Nothing too wild but the variation kept me on my toes.

Questions Asked (1)

Q1

Given a binary tree, return the values of the nodes visible from the right side, from top to bottom. The problem had a slight variation from the standard version.

Algorithms & Data Structures
Author's notes

Knew the base problem cold so I jumped straight to BFS level-order traversal and grabbed the last node at each level.

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AI HintsAI Generated

Suggested Approach

Clarify the variation first, then use BFS level-order traversal to capture the rightmost node at each level. If the variation involves a different traversal order or definition of 'visible', adapt accordingly and explain your reasoning.

Pro tip: Always ask clarifying questions about the variation before coding; it shows you don't assume and can handle ambiguity, which is crucial at Meta.

1. Clarify the Variation

Ask the interviewer to specify how the variation differs from the standard right-side view problem. Confirm the definition of 'visible' and traversal order.

2. Choose Traversal Strategy

Decide between BFS (level-order) or DFS (modified pre-order) based on the variation. Explain why your choice fits the problem constraints.

3. Outline Algorithm

Describe step-by-step how you'll traverse the tree and collect the rightmost nodes. Mention data structures like queues or recursion stacks.

4. Analyze Complexity

State time and space complexity (typically O(n) time, O(w) space for BFS where w is max width). Discuss trade-offs if using DFS.

5. Test with Examples

Walk through a sample tree, including edge cases like skewed trees or single nodes, to verify correctness and handle the variation.

Key Points to Mention

  • Level-order traversal using a queue to process nodes level by level
  • Tracking the last node at each level (rightmost) for the standard version
  • Handling the variation: e.g., if it's left-side view, adjust traversal order or node selection
  • Time complexity O(n) and space complexity O(w) for BFS, or O(h) for DFS
  • Edge cases: empty tree, single node, skewed tree (all left or all right)
  • Potential follow-up: optimize space or handle very large trees

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.