I spoke with an engineer at a career fair about my previous experiences and dropped off my resume. I was asked to sign up for a 30-minute on-campus interview that night for the following day.

Following the interview, I was asked to do another 60-minute interview the next day. Each of these was about 20% questions about goals and prior experience, and 80% coding.

After solving the problem, I could ask questions about Dropbox as a company. In two days, I was asked to visit the SF office for a full-day interview, which consisted of four one-hour interviews, each with one engineer and a shadow interviewer. I had lunch with another person in the middle, and it wrapped up with a 45-minute general Q+A.

Each interviewer was very nice and helpful. They tried to present questions to which I already had some prior knowledge based on my completed coursework and experience, so I didn't particularly feel out of my depth for any of it.

Implement two functions that assign and release unique IDs from a pool. Memory usage should be minimized, and the assign/release operations should be fast, even under high contention.