I had two phone screens. Facebook then flew me in from Europe for onsite interviews:

• 1 design interview
• 1 "culture fit" interview
• 4 coding/datastructures interviews

I did well in pretty much all of them, except for one coding interview. After about two weeks, the recruiter contacted me to say that they weren't able to make a decision. So, I had an extra phone interview with a "very senior" person a few days afterwards.

It was an enjoyable experience for the most part. The most significant issue was one interviewer who was obviously not ready to conduct interviews. He was completely unable to explain the problem I was supposed to solve and interrupted me every minute.

Write a program that solves linear equations with '+', '-', and '' operators, given as strings. For example, the input could be: "8+5+x+3x = 10-x+43x"