Haskell-Beispiele hinzugefügt

documents/Programmierparadigmen/scripts/haskell/lauflaengencodierung.hs

@@ -0,0 +1,21 @@
+splitWhen :: (a -> Bool) -> [a] -> ([a], [a])
+splitWhen _ [] = ([], [])
+splitWhen p (x:xs)
+        | p x       = ([], x:xs)
+        | otherwise = let (ys, zs) = splitWhen p xs 
+            in (x:ys, zs)
+-- >>> splitWhen even [1,2,3]
+-- ([1],[2,3])
+
+group :: Eq a => [a] -> [[a]]
+group [] = []
+group (x:xs) = let (group1, rest) = splitWhen (/=x) xs
+        in (x:group1) : group rest
+
+encode :: Eq a => [a] -> [(a, Int)]
+encode xs = map (\x -> (head x, length x)) (group xs)
+
+decode [] = []
+decode ((x,n):xs) = replicate n x ++ decode xs
+-- alternativ
+decode = concat . (map (\(x,n)->replicate n x))