Interview process got gradually more difficult, starting with easy questions and then going to more and more depth for heavy ones. Even for estimated, the expectation was to have them handy (memorized).

Around 2 months after I submitted my resume for Apple software engineer position, I got a call from the hiring manager. He asked me what was the good day for the interview. It took half day for meeting 5 people. It was long hour interview for me. Each interviewer spent ~ 30 minutes and asked ~ 4 questions. Each interviewer asked questions in the different areas.