+12 +13 +14 +15

1 files changed, 15 insertions, 0 deletions

diff --git a/h13.hs b/h13.hs
new file mode 100644
index 0000000..ec0a395
--- /dev/null
+++ b/h13.hs
@@ -0,0 +1,15 @@
+data ListItem a = Single a | Multiple a Int
+    deriving (Show)
+
+encode :: Eq a => [a] -> [(a,Int)]
+encode = foldr encodeHelper [] 
+    where 
+        encodeHelper a p@((x,c):ps) | x==a = (a,c+1):ps
+        encodeHelper a p = (a,1):p
+
+encodeDirect :: Eq a => [a] -> [ListItem a]
+encodeDirect = map encodeHelper . encode
+    where
+        encodeHelper (a,c)
+            | c>1 = Multiple a c
+            | otherwise = Single a