Run-length encoding: Difference between revisions

Line 2,431:

===In terms of group===

<lang haskell>import Data.List (group)

import Control.Arrow ((&&&))

-- Datatypes

type Encoded = [(Int, Char)] -- An encoded String with form [(times, char), ...]

type Decoded = String

-- Takes a decoded string and returns an encoded list of tuples

rlencode :: Decoded -> Encoded

rlencode = ~~map~~ (length ~~&&&~~ head) . group

rlencode = fmap ((,) <$> length <*> head) . group

-- Takes an encoded list of tuples and returns the associated decoded String

Line 2,447:

main :: IO ()

main = do

let input = "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW"

-- Get input

-- Output encoded and decoded versions of input

putStr "String to encode: "

encoded = rlencode input

input <- getLine

-- Output encoded and decoded versions of input

~~let~~ encoded = rlencode input

decoded = rldecode encoded

putStrLn $ "Encoded: " ++ show encoded ++ "\nDecoded: " ++ show decoded</lang>

putStrLn $ "Encoded: " <> show encoded <> "\nDecoded: " <> show decoded</lang>

<pre>Encoded: [(12,'W'),(1,'B'),(12,'W'),(3,'B'),(24,'W'),(1,'B'),(14,'W')]

Decoded: "WWWWWWWWWWWWBWWWWWWWWWWWWBBBWWWWWWWWWWWWWWWWWWWWWWWWBWWWWWWWWWWWWWW"</pre>

Or: