This feels like the question they expect you to finish in the given time, the "easy" question. The question I was ask was a bit harder, but in hindsight my unfamiliarity with the question made it feel harder than it was. The minimum expectation is a mostly complete and actually working implementation. I can't confirm this but my understanding is missing major edge cases means failing the interview. I am surprised the interviee started typing as quickly as she did, I believe I was asked to write more detailed pseudo code first.
There is a second more advanced technical interview asked after lunch. I didn't interview online, I interviewed in person so I am sure that changes some things.
I did not pass every stage of the onsite, but it was one of my better interviews experiences. No one applying to Jane Street does so without knowing how rigorous the process is, I don't hold it against them. It felt like everyone I met wanted me to pass the interview. I can't say that about every interview I have been on.
One thing that they don't tell you though, is that they don't consider last-year students for their internship, meaning you have to apply to graduate positions. One caveat though: about 80% of their graduate positions are filled with interns from precious years, and their openings for more experienced roles are few and far between because of the incredibly low turnover rate. I honestly feel like this isn't advertised very widely on their site.
Anyways, ~3 weeks after being told they were looking at my CV, I was rejected :( As sad as I am, I can at least take some solace in the fact that it took them so long to reject me.
That being said, after talking with the campus recruiter here in Hong Kong, I was told this video is a good representation of the first-round interview for interns and new-grads that is done over the phone. This interview is used as a minimum bar for your technical skills, as well as to assess your ability to explain technical concepts and work with others. If you pass this, you'd likely be invited to superday to attend the (4-8) subsequent technical interviews.
This is leetcode easy, medium at best. Quite shocking to me to be honest, as I envisioned this firm as an exclusive bunch of snobbish elitists.
