> I know a lot of people who can tweak code that already exists. However, if they are sitting in front of an empty text editor and given a goal, they don’t know how to break the problem down and build a solution with the tools the language gives them.

But being able to break things down and come up with a solution is not necessarily something that needs to be done quickly, in the time you have for an interview. Quite often I've been faced with a new problem and done absolutely nothing visible for ages. Literally just reading around the problem, asking questions, and sketching in my mind without writing a single line of code.

This is often faster and better than starting immediately.