I applied through their website and received a letter from them a week later. We scheduled an initial phone interview.

They don't conduct interviews via Skype or Hangouts, and their interviewers use an interactive codepad, similar to Collabedit.

I'd recommend plugging a headset into your phone. I didn't, so I had to constantly switch between holding my phone close enough to hear and typing code, which was very frustrating.

The interview lasted for an hour. The engineer I spoke with was nice and pleasant. He presented the problem to solve by giving a type signature for a function using OCaml, though you can use any programming language during the interview. Their blog post about their interviewing process specifically recommends candidates to "know their tools".

Upon discussing the last question, I believe he said something like "time's up." I guess that was the sign that my performance was subpar.

A week after the interview, I received a short, apologetic letter.

Implement a function memoize : (a -> b) -> (a -> b).

How would you bound the memory usage of this function?

What is a different approach to implement a FIFO buffer?