After five decades :)
soon learned that I'd have to adapt my playful coding approach to something more rigorous. Did I understand the problem I wanted to solve? Could I express it clearly? Could I communicate my understanding
Your (athough probably not now extant) lecturer in Systems Analysis is probably thinking FINALLY!
Once you understand a problem well enough to effectively and clearly communicate its requirements, AI is largely irrelevant. Invariably the structure of the problem defines the solution or at least constrains the feasible solutions. These solution(s) pretty much imply the classes at algorithms that could be used to realize them.
There are a surprisingly small number of basic or fundamental algorithms applicable to conventional computing. The explosion of implementions of these basic algorithms generally reflects the specialization of data structures and methods to efficiently implement the algorithm for a particular problem-solution case.
Modern coding environments like Python have a rich set of data structures and operations which facilitate the implementation of quite high level algorithms. Most also have large libraries of algorithms and further data structures.
As for the intellectual property question I think the author's employer's opinion that you own the copyright over the compilation is pretty much on the money.
This would bring the question more in line with literary works (fair dealing and all. :) Two murder mysteries novels by separate authors (say Margery Allingham and Dorothy L.Sayers) might use exactly the same plot devices (they don't) but would still be distinct non infringing works.
Personally I have always thought a lot less IP: copyright and patents in the software arena would have hastened development in all areas of IT.
It's not coincidental that the internet explosion occurred because of a critical mass of open source, largely unencumbered software (and to a much lesser extent hardware) and not in spite of it.
Any non trivial application would have a reasonably large number of possible implemention choices which should dearly bring it under the compilation copyright head without arguing about the implementation of a particular algorithm in one small part of the application.
Otherwise trade secret protection might be more appropriate.