Unless you are a superstar programmer, you are expected to do a coding exercise as part of interview process now days. I had a retired BBC journalist as a colleague at university. Very intelligent, focussed and an impeccable gentleman who could carry garish shirts in style. He gave me priceless advice on preparing my CV. He said, ‘CV is your chance to get to the interview stage, so, keep it to the point.’ You get the whole interview to impress the interviewer(s).
Why am I giving you tips on CV?
Because, the same idea can be applied to the coding exercises one does as part of the interview process. The coding exercise is a way for you to get a face-to-face interview. So, don’t stray away from the requirements. It’d be lovely to hear about how you will architect the system, but that’s not the point of the exercise. There’s absolutely no need to go over the required and miss the pivotal things in doing it. Produce what’s expected and you can impress them in the face-to-face interview.