A Facebook recruiter got in touch with me. We had a phone conversation. She set up a phone screen within a week.

I used Collabedit for coding, and there were two questions. I received a reply back within a week. An on-site interview was set up for the next week.

The on-site interview included:

• 1 behavioral interview
• Lunch
• 2 coding interviews
• 1 system design interview

The questions I received weren't super difficult, except for the system design question (how would you design the social graph with classes, interfaces, etc.?).

Other coding questions included:

• Implement pow(x, n)
• Convert from decimal to Roman numerals and vice versa
• Binary tree serialization and deserialization
• Implement a concurrent read/write buffer

For the system design question, the interviewer was very helpful and provided hints when I got stuck.

How will you design the social graph?