Question

I can’t use high order functions. I just can’t see to figure out how to do this. I am very new to haskell. It also has to be recursive.

split :: [Int] -> ([Int],[Int])
split xs = 

I am given this to start with. I honestly don’t even know where to start with this problem.

Examples:

split []
([],[])

split [1]
([1],[])

split [1,2,3,4,5,6,7,8,9,10]
([1,3,5,7,9],[2,4,6,8,10])

any help would be much appreciated.

Edit: Its even and odd positions.

So

split [3,6,8,9,10] would be
([3,8,10],[6,9])

ok so i came up with this. Its not pretty, but it seems to work ok.

split :: [Int] -> ([Int],[Int])
split [] = ([],[])
split [xs] = ([xs],[])
split xs = (oddlist xs, evenlist xs)

oddlist :: [Int] -> ([Int])
oddlist xs | length xs <= 2 = [head(xs)]
           | otherwise = [head(xs)] ++ oddlist(tail(tail(xs)))

evenlist :: [Int] -> ([Int])
evenlist xs | length xs <= 3 = [head(tail(xs))]
            | otherwise = [head(tail(xs))] ++ evenlist(tail(tail(xs)))

Answer 1

split [] = ([], [])
split [x] = ([x], [])
split (x:y:xs) = (x:xp, y:yp) where (xp, yp) = split xs