I major in CS at UC Berkeley and had been looking into how to get a job at companies in Silicon Valley, specifically Riot Games or Facebook. Essentially read everywhere about the application process and whatnot, and thought I'd ask a friend to refer me to work Facebook. The interview was just about 30-40 min and went pretty quickly. Two coding challenges and some interview questions. It was a campus recruiter so it must have been somewhat less intense.
I got the job! And now I work full-time out of college. Went pretty smoothly I must say. The coding challenges had to do with:
1. Print the above tree level by level
2. Hash mapping
3. Forgot the third one...
4. Project/thought process explanation
They stress the though process behind how you solve it the most, they enjoyed that I thought out loud and quickly from the very beginning (tip from my friend).
I'd recommend each and every one of you to find a connection into Facebook or the company you want to work for. My friend actually didn't have a friend who worked there. He was connected through some university career specialist. They pretty much, "prepped me like I was going into war" he said. They didn't even charge him so I'm not sure how their business model works.