+10

1 files changed, 20 insertions, 0 deletions

diff --git a/p10.hs b/p10.hs
new file mode 100644
index 0000000..68ffade
--- /dev/null
+++ b/p10.hs
@@ -0,0 +1,20 @@
+import Control.Applicative
+import Control.Arrow
+import Data.List
+
+encode :: Eq a => [a] -> [(a,Int)]
+encode = foldr elim []
+    where 
+        elim e [] = [(e,1)]
+        elim e p@(n:ns)
+          | e == fst n = (e,1 + (snd n)):ns
+          | otherwise = (e,1):p
+
+encode' (x:xs) = let (first,rest) = span (==x) xs
+    in (x,1+(length first)) : encode' rest
+
+encode' [] = []
+
+encode'' xs = map (head &&& length) $ group xs
+
+encode''' xs = map ((,) <$> head <*> length) $ group xs