tasks a-s

Task/Run-length-encoding/Haskell/run-length-encoding.hs

@@ -0,0 +1,24 @@
+import Data.List (group)
+
+-- 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 (\g -> (length g, head g)) . group
+
+-- Takes an encoded list of tuples and returns the associated decoded String
+rldecode :: Encoded -> Decoded
+rldecode = concatMap decodeTuple
+    where decodeTuple (n,c) = replicate n c
+
+main :: IO ()
+main = do
+  -- Get input
+  putStr "String to encode: "
+  input <- getLine
+  -- Output encoded and decoded versions of input
+  let encoded = rlencode input
+      decoded = rldecode encoded
+  putStrLn $ "Encoded: " ++ show encoded ++ "\nDecoded: " ++ show decoded