[sozin]

This interview question is good for kids recently out of school, but for everyone else I think it doesn’t really show if the candidate is a good developer.

Good taste — writing cohesive, loosely coupled code with a sensible bank of unit tests an a strong dose of product sensibility — is largely orthogonal to being good at solving algorithmic or ds questions. One of the best developers I know, who makes seven figures a year a year (trading software), would likely bomb the second part of this question. Contrawise, a young researcher I know who has won multiple scholastic programming competitions and crushes leet code, would destroy this problem in seconds … and yet, I pity his coworkers who have to live with his atrocious code.

More accurately, he would first look at the interviewer like he was a dolt, and then bomb the question :)