-- 4
ntoList  :: Integer -> [Integer] -> [Integer]
ntoList n l | (n == 0) = (reverse (filter even l))
            | otherwise = ntoList (div n 10) ( (mod n 10) : l )

listtoN :: [Integer] -> Integer
listtoN l = foldl (\x y -> x*10 + y ) 0 l


strangeCompare :: Integer -> Integer -> Ordering
strangeCompare a b = compare (listtoN (ntoList a [0])) (listtoN (ntoList b [0]))