A question like "how do you reverse a string" surely is like asking a chef to cook an egg? Any idiot can do it, it's got to be an opening on to "who are my customers?", "what are the cost and time constraints?", "what team members do I have?" "what's our angle" ...? If the answer is just "boil it for 5 minutes" then you know you're looking at someone with simplistic thinking; which is fine if you just need someone to mindlessly do as they're told. They might be an absolute expert at it.