better split in day 6

day6.hs

@@ -16,10 +16,7 @@ match as bs = (sort . nub) $ filter (`elem` bs) as
 
 split :: Eq a => a -> [a] -> [[a]]
 split _ [] = []
-split v as = split' v as [] []
-
-split' :: Eq a => a -> [a] -> [a] -> [[a]] -> [[a]]
-split' _ [] a as = as ++ [a]
-split' v (b:bs) a as
-  | b == v = split' v bs [] (as ++ [a])
-  | otherwise = split' v bs (a ++ [b]) as
+split d as = chunk : (split d rest)
+  where
+    chunk = takeWhile (/= d) as
+    rest = drop 1 $ dropWhile (/= d) as

split.hs

@@ -0,0 +1,6 @@
+split :: Eq a => a -> [a] -> [[a]]
+split _ [] = []
+split d as = chunk : (split d rest)
+  where
+    chunk = takeWhile (/= d) as
+    rest = drop 1 $ dropWhile (/= d) as