1) Questions about memory management. ARC vs MRC, Thread Safety (deadlock, race conditions), Blocks, Weak vs Strong references. I missed keeping strong refs to weak items during the block statement life cycle.
2) Coding question. Once I realized it was a permutation function and went strait to the recursion.
Sounds pretty good right? Wrong. I completely lost my noodle on part 2. I explained everything I wanted to do which checked out but everytime I went to write something it came out wrong. Perhaps it was interview anxiety. Immediately after the call I was so frustrated that I went ahead and finished the recursive problem myself.
I should say that shortly after this I was reinterviewed and after a series was flown out to the FB headquarters in CA. Cool experience, utimately not for me. The big 5 really just want coder monkeys; I want to be more creative than that.