The interview day consisted of 3 rounds, with 2 developers in each round.

They were most nice and open for questions.

It started with me explaining a major feature I designed over a whiteboard. The interviewers encouraged using the whiteboard to explain other answers as well.

You are given a code that implements a cache with a cleaner thread.

1. What does this code do?
2. Are there any problems with it?

You have millions of documents. Suggest a way to implement a system that enables querying which documents contain a specific word.

Follow-up #1: What if we want to query for two words?

Follow-up #2: Optimization of #1.

Some bizarre question related to time calculation:

Let's say you have a spaceship with a few systems and a central clock. In case one system is out of sync, how would you sync it with the central clock? Emphasize the round-trip time and the time it takes the central clock to actually get the current time.