I just went through a very special interview recently—— XAI Software Engineer positions. As a first-time NG (new grad) applicant, I didn’t have high expectations. Unexpectedly, HR took the initiative to contact me. The whole interview format was also quite magical, completely different from previous interviews with major companies. The whole process was fast-paced and had various question types that also gave me a lot of inspiration. Let me share my complete experience and preparation suggestions below, as a reference for students preparing for interviews with xAI or similar startups.
Compilation of common interview questions
In xAI’s SWE interview, I found that the questions can be roughly divided into five categories:
Algorithm class
Such as "Finding words using nine-square grid of letters (Trie + DFS)", LRU Cache implementation, etc. It mainly tests the mastery of data structure, boundary processing ability and coding ability. The overall difficulty is medium, and LeetCode's Word Search II, LRU Cache and other questions can be covered.
System design class
For example, in-memory database, cache system, and microservice architecture design. The focus of the inspection is architectural design capabilities, scalability considerations, and boundary and exception handling. During the interview, the interviewer pays more attention to the thinking process rather than the single answer.
XAI theory class
Involving the definition of Explainable AI, local vs. Global explanation, etc. Examine the candidate's understanding of model interpretability and how to communicate it to the business.
XAI Practice Class
For example, use SHAP/LIME to analyze models and improve fairness. Mainly examines tool usage ability and practical experience.
Behavioral class
Such as cross-team collaboration, problem solving, and project impact. Pay attention to communication skills, logical expression and team awareness.
Phone Screen
The electronic interview is the shortest and most efficient interview I have ever experienced, only 15 minutes. HR emphasizes that answers should be concise, basically in a "quick question, quick answer" rhythm. Frequently asked questions include:
- Describe the most technical project you have ever done in 30 seconds
- The two programming languages you are most familiar with
- What projects have you done using C++ and Python that were deployed to production?
In about 10 minutes, HR asked a dozen questions in a row, with almost no time to expand on the details, leaving 5 minutes for me to ask questions. Although the process was quick, I unexpectedly received an invitation from onsite and went nude (without any extra preparation).
Onsite interview process
Round 1: Jiugongge + Trie
This round is "Finding Words in Nine Squares of Letters", similar to the Boggle game. Given an NxN alphabet board and a dictionary, we need to find all the words that can be spelled out. I use Trie + DFS to backtrack. Trie quickly determines whether the prefix exists, DFS searches the path, and prunes if it does not match. In summary, it went smoothly, but this type of question can be covered by running Word Search II on LeetCode.
Round 2: LRU Cache
A classic question, requiring the implementation of get(key) and put(key, value), with a time complexity of O(1). The standard approach is hash table + doubly linked list. I'm fast at writing code, and in some cases I forget to update the tail pointer. Fortunately, I wrote a test case myself. I would like to remind everyone: the corner case must be covered. Don’t wait until the end to test it.
Round 3: In-Memory DB with Nested Transaction
Partial system design, making an in-memory database, supporting SET / GET / BEGIN / ROLLBACK / COMMIT, and supporting nested transactions. I first wrote the most basic data structure, and then discussed expansion with the interviewer: persistence can add logs or snapshots, consider concurrency control, and expansion can be distributed or master-slave replication. The interview atmosphere is relaxed and more about flexible thinking than standardized answers.
Interviews are never a one-man battle
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