Towers of Hanoi: Difference between revisions
m
→{{header|Haskell}}
Line 1,710:
<lang haskell>import Data.Monoid ((<>), mempty)
import Data.List (intercalate, transpose)
hanoi :: Int -> t -> t -> t -> [[t]]
hanoi 0 _ _ _ = mempty
hanoi n l r m =
hanoi (n - 1) l m r
<> [[l, r]]
<> hanoi (n - 1) m r l
showHanoi :: Int -> String
showHanoi n =
in unlines $ intercalate " -> " <$> transpose▼
-- TEST -------------------------------------------------------------
main :: IO ()
main = putStrLn $ showHanoi 5</lang>
▲ intercalate " -> " <$>
▲ ((justifyLeft 6 ' ' <$>) <$> transpose (hanoi 5 "left" "right" "mid"))
▲ justifyLeft n c s = take n (s <> replicate n c)</lang>
{{Out}}
<pre>left -> right
| |||