Optiver doesn't interview for a specific team, but rather first decides whether the company wants you and then places you in a specific position.

The first stage was a 48-hour challenge. The questions were all pretty basic, except for the last one, which took me a long time.

After that, there was a 30-minute HR interview.

Then a 45-minute technical interview, a lot of which was a discussion about the challenge.

After all that, I flew to Amsterdam for an on-site interview (Optiver covers flight and hotel expenses).

This included:

• Two technical interviews
• One HR interview
• One lunch with peers

The whole process was very positive. The recruiter was always available for any questions, and all the interviewers at all stages were very nice.

I had to give up the very nice offer they gave me because of personal reasons, but I think it could be a great company to work for.

Regarding trees, floating-point considerations are crucial for trading system design.