traversal on Binary Tree

Last updated: February 11, 2026

Quick Overview

Perform a rotation on a binary tree and return the result.

Lyft
Coding & Algorithms
Machine Learning Engineer
Lyft
February 11, 2026
Machine Learning Engineer
Take-home Project
Coding & Algorithms
Medium

135

11

106 solved


Perform a rotation on a binary tree and return the result.

Lyft uses this problem in the Take-home Project to evaluate your algorithmic thinking. They expect you to discuss multiple approaches, analyze trade-offs between them, and implement the optimal solution with clean, readable code.

What the Interviewer Expects
  • Recognize the underlying problem pattern (sliding window, two pointers, BFS/DFS, etc.)
  • Discuss multiple approaches and trade-offs before coding
  • Implement an optimal solution with clean, production-quality code
  • Handle all edge cases including boundary conditions and invalid input
  • Optimize both time and space complexity with clear justification
  • Test your solution systematically with well-chosen examples
Key Topics to Cover
Sorting and searching
Edge cases and input validation
Time and space complexity analysis
Hash maps and frequency counting
How to Approach This
  1. Clarify input constraints and edge cases before writing code.
  2. Walk through your approach verbally and confirm with the interviewer before coding.
  3. Start with a brute force solution, then optimize. Mention time and space complexity.
  4. Test your solution with examples, including edge cases like empty input or duplicates.
  5. Consider common patterns: sliding window, two pointers, hash map, BFS/DFS, dynamic programming.
Possible Follow-up Questions
  • How would you modify your solution to handle streaming input?
  • How would your solution change if the input was sorted?
  • What is the worst-case input for your solution?
  • How would you parallelize this solution?
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