I applied online. The process took 2 weeks. I interviewed at Jane Street (Hong Kong) in Sep 2023
Interview
It was over Zoom, and consisted of three questions. The interviewers emphasise that it should feel more conversational rather than test/question and answer. They want you to explain and step them through your thinking process regardless of the correctness of your approach.
Interview questions [1]
Question 1
If Worker A takes 1 hour to finish a job and Worker B takes 2 hours to finish a job. How long would it take them both to finish a job.
The interviewer was very informative. The questions appeared basic initially, but they required deeper reasoning, strong fundamental knowledge, and careful problem-solving instead of simple, straightforward answers throughout the interview process.
The process was structured and intellectually challenging. It typically involves an initial recruiter screen, followed by probability, mental math, expected value, and game-style problem-solving interviews. Interviewers focus more on reasoning, communication, and adapting to feedback than memorized answers.
Interview questions [1]
Question 1
You have two opaque boxes in front of you. At each turn, you may choose one of two actions:
Place: put one coin into one of the two boxes, chosen uniformly at random.
Take: choose one of the two boxes uniformly at random, take all the coins inside, and empty that box.
You play for exactly 100 turns. Your goal is to maximize the expected number of coins you collect.
What is your optimal strategy?
Several phone calls to go to the final round. The phone calls consists of mathematical, probabilistic brain teasers which was not that hard for a mathematics major. Final round was to harsh for me, strong mentality is required