+11

1 files changed, 15 insertions, 0 deletions

diff --git a/p11.hs b/p11.hs
new file mode 100644
index 0000000..77b7295
--- /dev/null
+++ b/p11.hs
@@ -0,0 +1,15 @@
+import Control.Arrow
+import Data.List
+
+data ListItem a = Single a | Multiple a Int
+    deriving (Show)
+
+encode :: Eq a => [a] -> [(a,Int)]
+encode xs = map (head &&& length) $ group xs
+
+encodeModified :: Eq a => [a] -> [ListItem a]
+encodeModified = map helper . encode
+    where
+        helper (a,1) = Single a
+        helper (a,c) = Multiple a c
+