I was first connected by a recruiter who found my profile on LinkedIn. The first step was a phone screening that asked 5 really simple questions about iOS and Objective-C (I think you have to score 3 out of 5 to pass this screening).

Then came a technical phone interview with a recruiter from Facebook. The interviewer picked the topic of memory management, including ARC. They also asked about KVC and KVO. I didn't do well with the coding challenge later, and that's why I think I wasn't going to the next round.

1. Describe how memory is managed in iOS (with Objective-C), and furthermore, what do retain() and release() do in Objective-C? Also, how did ARC improve memory management?

2. Had another coding challenge about the view hierarchy in iOS. It was actually a question about using recursive calling to retrieve a node from a binary tree that was copied from another tree. Sorry, I couldn't quite recall the actual question.