module Exercise05 where

import Data.List    

-- May or may not be useful: computes the logarithm base 2 (rounded down) of the given number.
-- You don't have to move this into the WETT tags if you want to use it.
log2 :: (Integral a, Num b) => a -> b
log2 = let go acc n = if n <= 1 then acc else go (acc + 1) (n `div` 2) in go 0

{-WETT-}
decompose :: [Integer] -> [Integer]
decompose ds 
    |elem 0 ds = []
    |elem 1 ds =[product ds]
    |otherwise = helper ds ds 0 : decompose (map (`div`2) ds)
   -- |otherwise = ：decompose (map (`div`2) ds)

    where helper _ [] sum = sum
          helper ds (x:xs) sum 
            | odd x = helper (delete x ds++[x-1]) xs (sum+product(delete x ds))
            |otherwise =helper ds xs sum   
     
{-TTEW-}