module Exercise_7 where
import Data.List
import Data.Maybe
import Data.Function

{-WETT-}
trancl :: Eq a => [(Integer,(a,a))] -> [(Integer,(a,a))]
trancl xs | xs == ys = ys
          | otherwise = trancl ys
          where
            ys = nubBy (on (==) snd) $
                 sortOn fst $
                 xs ++
                 concatMap (\(ia, (fa,sa)) ->
                 [(ia + fst b, (fa, snd $ snd b)) | b <- filter ((sa ==) . fst . snd) xs]) xs
{-TTEW-}