inversion on Binary Tree
Last updated: August 1, 2025
Quick Overview
Given a binary tree, write a function to invert the tree, meaning that for every node, its left and right children are swapped. The function should take the root of the binary tree as input and return the root of the inverted binary tree.
Rippling
August 1, 2025151
8
176 solved
Given a binary tree, write a function to invert the tree, meaning that for every node, its left and right children are swapped. The function should take the root of the binary tree as input and return the root of the inverted binary tree.
Rippling 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
How to Approach This
- Clarify input constraints and edge cases before writing code.
- Walk through your approach verbally and confirm with the interviewer before coding.
- Start with a brute force solution, then optimize. Mention time and space complexity.
- Test your solution with examples, including edge cases like empty input or duplicates.
- Consider common patterns: sliding window, two pointers, hash map, BFS/DFS, dynamic programming.
Possible Follow-up Questions
- How would you test this solution thoroughly?
- Can you solve this in a single pass?
- Can you optimize the space complexity of your solution?
Sharpen Your Skills on Codemia
Practice similar problems with our interactive workspace, get AI feedback, and track your progress.
Practice DSA ProblemsSample Answer
Problem Analysis
The problem at hand requires us to invert a binary tree, which involves swapping the left and right children of every node in the tree. The underlying pattern that applies here is Depth-First Search (...
Approach
We can solve this problem using a recursive approach. The algorithm will follow these steps:
- If the current node is null (base case), return null.
- Recursively invert the left subtree.
- Recursi...
Submit Your Answer
