Find connected components in binary tree
Last updated: March 27, 2026
Quick Overview
Given a binary tree, write a function to find all connected components, where a connected component is defined as a set of nodes that are reachable from each other through their parent-child relationships. The function should return a list of lists, where each inner list contains the values of the nodes in a connected component. The input will be the root node of the binary tree, and the output should be a list of connected components.
Roblox
March 27, 202645
4
405 solved
Given a binary tree, write a function to find all connected components, where a connected component is defined as a set of nodes that are reachable from each other through their parent-child relationships. The function should return a list of lists, where each inner list contains the values of the nodes in a connected component. The input will be the root node of the binary tree, and the output should be a list of connected components.
This coding problem is frequently asked during Phone Screen at Roblox. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. Roblox expects candidates to write production-quality code, not just solve the puzzle.
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
- What is the worst-case input for your solution?
- How would you modify your solution to handle streaming input?
- How would you parallelize this solution?
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Practice DSA ProblemsSample Answer
Problem Analysis
In this problem, we are tasked with finding all connected components in a binary tree based on parent-child relationships. A connected component is defined as a set of nodes that can reach each other ...
Approach
- Initialize a list to hold connected components: Create an empty list to store the resulting connected components.
- Perform DFS traversal: Start from the root node and perform a DFS. For e...
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