i dont really think anyone cares if somethings been copy/pasted as long as it works as it should, the most talented engineer i ever met told me theres no need to be ashamed of it, theres no point reinventing the wheel if you dont have to, and he was right if youve been able to adapt something else to your task then evidently you understand what it does.

lets say youre building a car, maybe you take the engine from a ford and mount it on the chassis of renault with nissan steering, just because you didnt design those parts from the ground up doesnt make the end result any less valid as a final product (obviously thats a very loose analogy but you get the picture)

software is a bit different though, rather than showing that you followed a rigorous formula its about letting people know how the formula you came up with works