Went to career fair, applied to Facebook and the recruiter said she could also pass my resume to WhatsApp. Within a week I got an email from WhatsApp scheduling an on-campus interview. The on-campus interview was pretty easy. They asked me to implement a Linked List with some special functions such as prepend, reverse and stuff, with some runtime requirements. Later they also asked me about parallelism. After that, about a week or so, I got an onsite interview. The onsite interview was SUPER hard. It was three different people in a row (but all technical/design questions), each for a hour. Two data structure questions (super hard) and one design question. After the first one I was sure that I would not pass, as the interviewer said "terrible" to the people outside the door. Indeed, after two weeks I got rejected via email.