Similar to others mentioned here:

• Contacted via LinkedIn
• One screening call (45 minutes)
• On-site with four 45-minute interviews.

Overall, the algorithm questions are not particularly hard. I have interviewed with FB twice, and both times felt the sessions went well (although considerably better the second time), but I received no offer either time. You won't get detailed enough feedback to know where you might have tripped up, if anywhere.

From their point of view, I think this is understandable, but it makes it harder to deal with the rejection. If you had fouled up every session, you would feel better than if you basically answered all the questions, with seemingly positive feedback from each interviewer, yet did not get an offer.

As noted elsewhere, it's probably best to be stoic about the whole thing and accept that they have so many candidates they probably apply a "benefit of the doubt" policy that works against you. I would imagine they employ a sort of "thumb up," "thumb down" policy.

They are, however, very pleasant and you can expect to have a positive experience of the process even if the result is not what you might want for yourself.

One session is for higher-level design, while the rest are standard algorithm sessions. All of this is explained in advance, so there are no surprises. One on-site session is a more traditional interview.