Programming "puzzles" in interviews are not made with the intention of tricking you. They aren't designed to make you find some metaphorical needle in a haysta

Programming "puzzles" in interviews are not made with the intention of tricking you. They aren't designed to make you find some metaphorical needle in a haystack, either. They're designed to be easy problems with clear avenues or multiple avenues of attack to solve. And people asking them are well aware that applicants sometimes get stuck, which is why they ask multiple questions (unless applicants get stuck on the easy warm-up question).