The interview process involved four rounds.

The first round was an online test, consisting of 10 basic problems and 2 coding challenges. It was simple.

Next was a phone interview with the manager, which included a coding test.

Then, a phone interview with an engineer followed, where I was asked to design a C++ compiler. This was also straightforward.

The third phone interview presented a bizarre problem to solve. This interview was conducted by a "total moron." Even the recruiter was surprised at how well I performed in the first three rounds and how poorly the fourth round went.

Afterward, I could have proceeded to another round. However, I decided I would not like to work with the "moron" I encountered in round 4 and informed the recruiter that I did not wish to continue.

Nothing difficult.