Well, if it’s for an assignment that you were specifically told to write everything completely yourself, then yeah, I guess you can call it cheating. If it’s open source that your referencing from and you use their algorithm that they made so others could use it, then nah. That’s just being practical imo. No reason to re-invent the wheel. You might as well call frameworks cheating as well.
Is it considered cheating if I use the SHA-256 hashing algorithm for whatever program instead of inventing my own? Hell no. It’d be ridiculous and completely insecure to write my own. Only reason I’d do it (and am) is for fun and/or learning.
For learning purposes I would 100% suggest trying to do everything yourself though. But don’t be afraid to google. Don’t google the solution, but google a certain part of your problem. Look at a reference manual or book.
In the case of this course though, yeah I’d consider it “cheating”. But the only person you’d be cheating is yourself out of actually learning.