Transform string to tree
Last updated: December 15, 2025
Quick Overview
Convert the given string to sorted result following the specified rules.
Uber
December 15, 202520
12
3,984 solved
Convert the given string to sorted result following the specified rules.
This coding problem is frequently asked during Take-home Project at Uber. The interviewer is testing your ability to translate a problem into clean, working code while discussing time and space complexity. Uber 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
- How would you test this solution thoroughly?
- Can you solve this in a single pass?
- What is the worst-case input for your solution?
- What if the input doesn't fit in memory?
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Brute Force Approach
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