inversion on Binary Tree

Last updated: December 27, 2025

Quick Overview

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

Airbnb
Coding & Algorithms
Software Engineer
Airbnb
December 27, 2025
Software Engineer
Phone Screen
Coding & Algorithms
Medium

21

14

2,735 solved


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

Airbnb uses this problem in the Phone Screen 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
Binary search and divide and conquer
Sorting and searching
Tree structures and recursion
Common algorithm patterns (sliding window, two pointers, BFS/DFS)
Data structure selection and trade-offs
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 parallelize this solution?
  • What if the input doesn't fit in memory?
  • How would your solution change if the input was sorted?
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