Uber | SDE 2 | Bangalore | July 2024 [Offer]

Online Assessment

My interview process began with an Online Assessment, which consisted of three questions, all ranging from LeetCode Easy to Medium difficulty. I successfully solved all of them with all test cases passing.

Technical Phone Screen

Following the OA, I moved to a Technical Phone Screen. The question was to find the minimum absolute difference between any two elements within every K-sized rolling window of a given N-sized array. I managed to implement a working solution with O(NKlogK) time complexity. However, the interviewer expected a more optimal O(NlogK) solution. The idea behind this optimal approach involves a one-time construction of a K-sized sorted set for the first window and a K-1 sized sorted set of differences, which takes O(KlogK). Subsequent window operations (removal, addition, and minimum difference computation) can then be performed in O(logK) each, leading to the overall O(NlogK) complexity. Although I couldn't implement or clearly discuss the optimal solution, I surprisingly still received an onsite interview call.

Onsite DSA

The onsite DSA round had two questions. The first was to construct an N-sized array containing elements from 0 to N-1, given K subsequences of that array. A follow-up asked to return the 'lowest' value solution in case of multiple valid arrays. I was able to solve both the question and the follow-up with optimal time complexity, using topological sort for the first part and a minor modification to the DFS for the second part to ensure descending order traversal. The second question was a string manipulation problem, similar to one found in this post. I implemented a working solution. We discussed that a Trie might be overkill given the limited element set, and the interviewer agreed, so a simple hash-map based approach sufficed.

LLD

For the Low-Level Design round, I was asked to design a well-defined logging library API with get and set methods, where data was expected to be handled in memory. I first implemented a functionally complete solution, incorporating appropriate design patterns like singleton and fluent interfaces. We then discussed and partially implemented improvements, including concurrency handling with locking and time complexity optimization. I encountered some strange compilation issues while working on the optimization, preventing me from fully completing all discussed requirements, but there were no major gaps.

HLD

The High-Level Design round involved a problem statement that the interviewer copy-pasted, rather than verbally discussing. While I don't recall the exact problem statement, it was well-defined, which made the interview more straightforward than usual HLD rounds.

Hiring Manager

Finally, the Hiring Manager round consisted of several behavioral questions and cross-questioning, with a significant focus on my experience managing multiple stakeholders.

Notes

Overall, the interviews were comprehensive and covered standard topics. I found that the most challenging part of the process was getting the initial call from the recruiter, which required personal referrals and patience.