module Exercise_7 where

import Data.List

{-WETT-}
comp ::
     Eq b => [(Integer, (a, b))] -> [(Integer, (b, c))] -> [(Integer, (a, c))]
comp [] _ = []
comp ((i, (a, b)):fs) ss =
  (map (\(i2, (_, c)) -> (i + i2, (a, c))) (filter ((== b) . fst . snd) ss)) ++
  comp fs ss


trancl :: Eq a => [(Integer, (a, a))] -> [(Integer, (a, a))]
trancl rs
  | rs == next = rs
  | otherwise = trancl next
  where
    all = rs ++ comp rs rs
    next =
      nub $
      filter
        (\(i, (a, b)) ->
           find (\(si, (sa, sb)) -> sa == a && sb == b && si < i) all == Nothing)
        all
{-TTEW-}