Next highest int from digits: Difference between revisions

<lang haskell>import Data.List (unfoldr)

digitShuffleSuccessors

:: Integral b

else Just (ds, (go . reverse) ds))

(go (reversedDigits n))

minimalSwap

:: Ord a

let (less, h:more) = break (> pivot) reversedSuffix

in reverse (h : prefix) ++ less ++ pivot : more

---------------------------TEST----------------------------

main :: IO ()

digitShuffleSuccessors

[0, 9, 12, 21, 12453, 738440, 45072010, 95322020]

putStrLn $

fTable

(take 10 . digitShuffleSuccessors)

[9589776899767587796600]

--------------------------GENERIC--------------------------

reversedDigits

go 0 = []

go x = rem x 10 : go (quot x 10)

splitBy :: (a -> a -> Bool) -> [a] -> ([a], [a])

splitBy f xs = go $ break (uncurry f) $ zip xs (tail xs)

go (ys, zs)

| null ys = ([], xs)

| otherwise = (fst (head ys) : map snd ys, map snd zs)

unDigits

:: (Foldable t, Num a)

=> t a -> a

unDigits = foldl (\a b -> 10 * a + b) 0

--------------------------DISPLAY--------------------------

fTable :: String -> (a -> String) -> (b -> String) -> (a -> b) -> [a] -> String

where

w = maximum (length . xShow <$> xs)

rjust :: Int -> Char -> String -> String

rjust n c = drop . length <*> (replicate n c ++)</lang>