RosettaCodeData/Task/Set-consolidation/Haskell/set-consolidation.hs
2019-09-12 10:33:56 -07:00

26 lines
701 B
Haskell

import Data.List (intersperse, intercalate)
import qualified Data.Set as S
consolidate
:: Ord a
=> [S.Set a] -> [S.Set a]
consolidate = foldr comb []
where
comb s_ [] = [s_]
comb s_ (s:ss)
| S.null (s `S.intersection` s_) = s : comb s_ ss
| otherwise = comb (s `S.union` s_) ss
-- TESTS -------------------------------------------------
main :: IO ()
main =
(putStrLn . unlines)
((intercalate ", and " . fmap showSet . consolidate) . fmap S.fromList <$>
[ ["ab", "cd"]
, ["ab", "bd"]
, ["ab", "cd", "db"]
, ["hik", "ab", "cd", "db", "fgh"]
])
showSet :: S.Set Char -> String
showSet = flip intercalate ["{", "}"] . intersperse ',' . S.elems