module CardShuffle where

cut xs = splitAt n xs where n = length xs `div` 2

riffle (x:xs, y:ys) = x : y : riffle (xs,ys)
riffle (xs  ,   ys) = xs ++ ys

shuffle = riffle . cut

apply n f = if n==0 then id else f . apply (n-1) f

count f x = 1 + ch (f x)
            where ch y = if x==y then 0 else 1 + ch (f y)

counts = map (count shuffle) [[1..n] | n <- [1..]] :: [Int]

row (i,n) = show i ++ "\t" ++ show n ++ ":\t" ++ take n (repeat '#')

graph n  = mapM_ (putStrLn . row) (zip   [1..n]        counts)
graph' n = mapM_ (putStrLn . row) (zip [0,2..n] (evens counts))

evens (x:_:xs) = x : evens xs
evens xs = xs






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rank = ("A23456789XJQK" !!)
suit = (["♦","♣","♥","♠"] !!)

red s = "\ESC[31m" ++ s ++ "\ESC[0m"

card n = (if even (n `div` 13) then red else id) (rank r : suit s)
         where (s,r) = n `divMod` 13
--       where (r,s) = n `divMod` 4

prt = unwords . map card

deck, six :: [Int]
deck = [0..51]
six = [0..23]

try n cs = do  putStr (show n ++ ":\t")
               putStrLn (prt cs)
               while (n > 0) (try (n-1) (shuffle cs))

run cs = do  putStr ("\n\t" ++ prt cs)
             c <- getLine
             while (c /= "q") (run (shuffle cs))

while b p = if b then p else return ()