Because of my good rank in code sprint 2, a Facebook recruiter contacted me and arranged a phone interview. After a week, I got a technical interview with a Facebook engineer.
The problems include:
1. Design a new feature for Facebook
2. C++ knowledge questions about static and virtual function
3. Implement a function to compute cubic root
Too bad that I didn't notice that the cubic root can be larger than the original number. I got rejection after 2 days.