Mind boggling card trick: Difference between revisions
→{{header|Haskell}}: Swapped to a more direct (recursive) formulation of threeStacks
(→{{header|Haskell}}: Swapped to a more direct (recursive) formulation of threeStacks) |
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import Data.Monoid ((<>))
-- RED vs BLACK ----------------------------------------▼
rb :: Int -> Char▼
rb n▼
| even n = 'R'▼
| otherwise = 'B'▼
-- THREE STACKS ----------------------------------------▼
threeStacks :: String -> (String, String, String)▼
threeStacks cards =▼
main :: IO [Int]
main = do
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]
return ns
▲-- RED vs BLACK ----------------------------------------
▲rb :: Int -> Char
▲rb n
▲ | even n = 'R'
▲ | otherwise = 'B'
▲-- THREE STACKS ----------------------------------------
▲threeStacks :: String -> (String, String, String)
▲threeStacks cards = go ([],[],[]) cards
where
go tpl [] = tpl
go (rs, bs, ds) (x:[]) = (rs, bs, x:ds)
go (rs, bs, ds) (x: y: xs)
| 'R' == x = go (y:rs, bs, x:ds) xs
| otherwise = go (rs, y:bs, x:ds) xs
-- SHUFFLE -----------------------------------------------
| |||