The mapHelper version that was rejected changed the order. The one that did `List.reverse` had the correct order, and this one is equivalent to the List.foldr solution.
The only difference is List.foldr's implementation is more performant (up to a certain number of elements as you say). If this is not what you asked, then I did not understand the question.
The only difference is List.foldr's implementation is more performant (up to a certain number of elements as you say). If this is not what you asked, then I did not understand the question.