Apple Software Engineer interview questions

I was referred by a current Apple employee. The recruiters were very quick and responsive during the whole process. It took less than 2 days to schedule the first interview after I was referred. 1 hour phone screen followed by a 4 hour virtual onsite. Each interview focused on a different question/problem. All problems were solved/worked through using pseudocode, I never actually had to run any code. No behavioral interviews other than a few teamwork questions sprinkled in the technical interviews.