Revision: 49755
Updated Code
at July 29, 2011 08:06 by rtperson
Updated Code
data EncodedElement a = Multiple Int a | Single a
deriving Show
encodeModified :: (Eq a) => [a] -> [EncodedElement a]
encodeModified = map (\x -> if (length x > 1)
then Multiple (length x) (head x)
else Single (head x)) . group
decodeModified :: [EncodedElement a] -> [a]
decodeModified = concatMap decode
where
decode (Multiple n c) = replicate n c
decode (Single c) = c : []
Revision: 49754
Initial Code
Initial URL
Initial Description
Initial Title
Initial Tags
Initial Language
at July 29, 2011 08:03 by rtperson
Initial Code
data EncodedElement a = Multiple Int a | Single a
deriving Show
encodeModified :: (Eq a) => [a] -> [EncodedElement a]
encodeModified = map (\x -> if (length x > 1)
then Multiple (length x) (head x)
else Single (head x)) . group
isMultiple :: EncodedElement a -> Bool
isMultiple x = case x of
Multiple _ _ -> True
Single _ -> False
decodeModified :: [EncodedElement a] -> [a]
decodeModified = concatMap decode
where
decode (Multiple n c) = replicate n c
decode (Single c) = c : []
Initial URL
http://www.haskell.org/haskellwiki/99_questions/11_to_20
Initial Description
problem 11, modified run-length encoding
========================================
If an element has no duplicates, mark it as such.
Example:
encodeModified "aaaabccaadeeee"
[Multiple 4 'a',Single 'b',Multiple 2 'c',
Multiple 2 'a',Single 'd',Multiple 4 'e']
problem 12, Decode a run-length encoded list.
=============================================
Given a run-length code list generated as specified in problem 11. Construct its uncompressed version.
Example:
decodeModified
[Multiple 4 'a',Single 'b',Multiple 2 'c',
Multiple 2 'a',Single 'd',Multiple 4 'e']
"aaaabccaadeeee"
Initial Title
Haskell 99 Problems - Solutions to 11 and 12
Initial Tags
Initial Language
Haskell