Munchausen numbers: Difference between revisions

Or, without digitToInt, but importing join and swap.

<lang haskell>import Control.Monad (join)

import Data.List (unfoldr)

import Data.Tuple (swap)

isMunchausen :: Integer -> Bool

isMunchausen = (==) <*> (foldr ((+) . join (^)) 0 . unfoldr digit)

digit 0 = Nothing

digit n = Just $ swap (quotRem n 10)

main :: IO ()

main = print $ filter isMunchausen [1 .. 5000]</lang>