Optimize flattening for without recursion
Last updated: December 10, 2025
Quick Overview
Given a nested list of integers, implement a function to flatten the list into a single-level list without using recursion. The function should take the nested list as input and return a flat list containing all the integers in the same order they appear.
Roblox
December 10, 2025538
14
1,099 solved
Given a nested list of integers, implement a function to flatten the list into a single-level list without using recursion. The function should take the nested list as input and return a flat list containing all the integers in the same order they appear.
Coding interviews at Roblox focus on problem-solving approach as much as the final solution. The interviewer wants to see you break down the problem, consider edge cases, and optimize iteratively. Communication throughout the process is key.
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
- Can you solve this in a single pass?
- How would you test this solution thoroughly?
- What if the input doesn't fit in memory?
- 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
This problem can be approached using a stack-based iterative method, which is a common pattern for flattening nested structures. The main challenge is to traverse through a potentially deeply nested l...
Approach
- Initialize an empty list
flat_listto hold the final flattened integers and a stack with the input nested list. - While the stack is not empty, pop the top item.
- If the popped item is an in...
Submit Your Answer
