The interviewing process was extremely unprofessional.

I had an interview scheduled with an interested hiring manager, but on the day of the interview, I never received a call.

I emailed the recruiter and only after doing so did they tell me the position was already filled. The lack of advanced notice until after the interview would have taken place was incredibly impolite.

I also interviewed with them at a conference last year, where I was forced to interview for both an area and language I was unfamiliar with.

My interviewer was on his phone the whole time and wasn't helpful at all.

As stated, I never got an interview. However, in the previous year, I received questions on data structures and operating systems.