Why can't you reverse a string with a flag emoji?
So, in terms of acing interviews, increasingly one of the best answers to the question "Write some code that reverses a string" is that in a world of unicode, "reversing a string" is no longer possible or meaningful.<p>You'll probably be told "oh, assume US ASCII" or something, but in the meantime, if you can back that up when they dig into it, you'll look really smart.