{-# LANGUAGE ExplicitForAll #-}
module Exercise_7 where

import Control.Monad
import Data.List
import Data.Functor
import Data.Function (on, fix, (&))
import Text.Parsec (string, choice, char, try, sepBy1, noneOf, many1, parse, eof, optional, many)
import Text.Parsec.String (Parser)
import qualified Data.Set as Set

{-WETT-}
into' :: Eq b => Ord a => [(a, b)] -> (a, b) -> [(a, b)]
into' [] = pure
into' (f:fs) = \v ->
    if snd v == snd f
        then (fst v `min` fst f, snd v) : fs
        else f : into' fs v

trancl' :: Eq a => [(Integer,(a,a))] -> [(Integer,(a,a))]
trancl' r = foldl' into' mzero $ r ++ [(a1 + b1, (fst a2, snd b2))
                                      | (a1, a2) <- r, (b1, b2) <- r, snd a2 == fst b2]


trancl :: Eq a => [(Integer,(a,a))] -> [(Integer,(a,a))]
trancl r =
    if trancl' r == r
        then r
        else trancl $ trancl' r
{-TTEW-}