collect maximum elements of a list in one pass

collectMaxs.hs

-- Got inspiration from http://izzycecil.com/posts/2015-07-29-circular.html

trace :: (a -> c -> (b, c)) -> a -> b
trace f a = b
  where (b, c) = f a c

collect' :: (Ord a)  => (a -> a -> a) -> [a] -> a -> ([a],a)
collect' f [x] m = ([m],x)
collect' f (x:xs) m =
  let (replaced, m') = collect' f xs m
  in ( if compare m x == EQ
         then m : replaced
         else replaced
     , f x m')

collect
  :: (Ord a)
  => (a -> a -> a) -> [a] -> [a]
collect f = trace (collect' f)

collectMaxs = collect max