Jane Street Software Engineer - Intern interview questions

3 phone calls, then on-site interviews (also three). Questions vary: some algorithm questions, also design questions and questions involving functional programming (I would tell it is not such important to know OCaml, but concepts of functional programming [monads, types, tail recursion] - I would tell that it was not "basic" functional programming, but these more difficult concepts). Everyone is professional, it was easy to understand what they are asking and you can ask questions to get clarifications.

They came to our university and gave a talk, so I send them my resume and attended a phone interview days later, the guy who interviewed me was very nice and I kind of felt that he was the smartest person who ever interviewed me. it was a pleasant experience, but sadly I got rejected soon after the interview, lol.