Apple Software Engineer interview questions

I got a call from the HR seeing my resume online. I applied for compiler developer position and they called me for a position in the LLVM team. I had 2 levels of phone interview and finally didn't get through though. I had first level of interview with a Director who asked questions about my Masters research work and then I had another level with the manager and a developer who asked me general questions about my resume. The interview lasted for 30-40 min.

I received initial communication by email from a recruiter that a hiring manager would like to set up a time to talk. I had 2 phone interviews, and then flew out for 12 in person interviews (members of the team and management chain). Everything went really well. The people were really nice and it was great talking with them. The logistics were all handled well. I was basically told I had the job. Unfortunately, a few days after I was told there was a hiring freeze. The process dragged on for months. 2 more phone interviews, followed by 2 months wait, and another 2 phone interviews which were the last. Eventually, I was told they would not move forward. Further inquiry explained they were unable to obtain a job requisition.