Jane Street Software Engineering Intern interview questions

I was contacted via email to set up the first of a series of phone screens. I ended up having three interviews before being informed that I would not be continuing in the process. The first person I talked to was very kind, but things were difficult because it was hard to understand his accent. In the end this was not a problem because he and I could type to each other via the collaborative editing website we were on. I heard back about a second screening via email less than 15 minutes after the call ended. The second person called almost half an hour late, and seemed irritated at the beginning, but things worked out well from there. I had some trouble solving the question, but he said he picked the question precisely because most people have trouble with it. I received an email to set up another interview about 3 days later. The third person really threw me off. He seemed personally offended that my school re-implemented parts of a language's core library for instructional purposes about cost bounds. We were interrupted on his end multiple times, and even though he had called a little late, he started trying to leave about halfway through. I know he had other things to do, but I did as well; that's why I cleared my schedule. There were multiple times I would say something (including questions), expecting a response, and get nothing, which made me suspect he had brought other work in with him. I pretty much knew I wouldn't be getting an offer after the third interview, not only because the interviewer seemed so disinterested, but mainly because I performed rather poorly on that question.

Was contacted by the recruiter at my school, who set up an on-campus interview for me. I was informed a few days later that I didn't make it to the next round. The interviewer was cold and seemed disinterested. He wasn't helpful when I asked questions or clarifications about the problem.