Problem 15 Solutions

Solution 1 - recurse

repeatElements : Int -> List a -> List a
repeatElements n list =
    case list of 
        [] -> []

        x :: xs -> 
            (List.repeat n x) ++ repeatElements n xs

Solution 2 - concatMap

repeatElements : Int -> List a -> List a
repeatElements n list =
    List.concatMap (\x -> List.repeat n x) list

Solution 3 - fold

repeatElements : Int -> List a -> List a
repeatElements n list =
    List.foldl (\x y -> y ++ (List.repeat n x)) [] list

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