One technological interview on-site. At first with a group leader and after that with a team leader. The questions were quite easy... After this interview I had an interview with the head of the product which wanted to mainly explain about the company and the product and to understand what I have recently done (the projects I've worked on).

Then I had a regular interview with HR with the usual question "Why do you think your skills are good for this role?", "What is your expected salary?" and stuff...

At the end I had an interview with the CEO that mainly talked about the company.

Discover a bug in a C++ code and suggest a fix for it.