Cracking the Zoom 技术电面: Insights on LRU Cache & Unexpected Challenges

Software Engineering
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zoom | Technical Phone Interview | Interview Experience

Interview Date: Not specified
Result: Not specified
Difficulty: Not specified

Interview Process

The interview was conducted by the hiring manager. It began with questions about my project experience, which felt somewhat formulaic. I was then asked a LeetCode question related to implementing an LRU Cache.

In the first technical round, I was asked a LeetCode question about finding words in a 2D grid, where the optimal solution involved a trie. I provided a suboptimal answer, and there was a hidden issue in my initialization that led to a bug.

The second round, named DeepDive, lasted about 10-15 minutes. The interviewer seemed unfamiliar with PyTorch and the questions suggested they were not focused on model development, particularly not on LLMs or Transformers. We worked through two LeetCode problems, one involving trees and another related to top K elements.

In the third round, named MLSD, the interviewer started by stating we would solve two LeetCode problems. I pointed out that the interview was supposed to focus on MLSD. We then tackled a dynamic programming problem and discussed a system design question. I also had a brief conversation about the actual job requirements.

Overall, the interviewers were decent, but it became clear that their real need was for a Software Engineer rather than a Machine Learning Engineer. The interview was primarily conducted in Chinese, which was unexpected since I felt it should have been in English.

In the end, I received feedback indicating that my code contained bugs and that a stronger candidate was selected. I understood this and felt indifferent but was curious about any useful feedback. It was puzzling why I was asked five LeetCode questions across four rounds without any machine learning case studies or design discussions. The interviewers seemed to be focused more on systems rather than my area of expertise.

Technical Questions

  1. LRU Cache (Hash Table, Deque)
  2. Finding words in a 2D grid (Trie)
  3. Tree-related problem
  4. Top K elements
  5. Dynamic Programming problem

Tips & Insights

  • Be prepared for questions that may not directly relate to the position you are applying for.
  • Consider the interview language and be ready to switch if necessary.
  • Clarify the focus of the interview early on to align expectations with the interviewers.