I got the interview on campus. There were 2 coding questions. It went well and I could solve the problems, even though I got stuck on explaining complexity and answered them incorrectly. But the interviewer explained me the correct answer and how to calculate it. I thought I wouldn't pass, but I made it and had to fly to Menlo Park!
The experience at Facebook HQ was great. Nice weather. Nice people (candidates and campus tour guide). Nice food! There was only 1 interview in the morning (I heard there were 3 rounds for full-time). It was 45 minutes, consists of general questions and 1 coding question. I didn't do well for the coding one. I couldn't solve the problem and tried so many ways to solve it. Finally, the interviewer gave me the approach to solve it, and let me code. I didn't code well though, so many mistakes. After the interview, I had a tour around the campus. I still shocked from the interview and thought I wouldn't pass.. and I didn't :)
However, I really had a great time at Facebook HQ. I thought about the question again and it wasn't hard.. I had to be more prepared!
PS. Don't take limo!!! They won't reimburse you for that!!!