Very standard question. Interviewer didn't communicate how much time I was allowed to code in the first place. I finished the main part and the second part is straightforward. I was asked to stop coding after 45min passed, though I think I can finish the next part in a short amount of time. I interviewed many iOS engineers and passed interview in similar format at other companies. I got a feeling that they are testing out the interview questions and process, as it seems no one is dedicated to mobile dev work.