RosettaCodeData/Task/Multiplication-tables/Haskell/multiplication-tables-2.hs

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Haskell
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2019-09-12 10:33:56 -07:00
import Data.List (groupBy)
import Data.Function (on)
import Control.Monad (join)
main :: IO ()
main =
mapM_ print $
fmap (uncurry (*)) <$>
groupBy
(on (==) fst)
(filter (uncurry (>=)) $ join ((<*>) . fmap (,)) [1 .. 12])