day 6 done woooo

day6.hs

@@ -0,0 +1,25 @@
+import Data.List (nub, sort)
+
+main :: IO ()
+main = do
+  raw <- readFile "day6.txt"
+  let ls = map concat $ split "" $ lines raw
+      ms = split "" $ lines raw
+      ansA = sum $ map (length . nub) ls
+      ansB = sum $ map (length . (foldr match ['a'..'z'])) ms
+   in do 
+     putStrLn $ "day6a: " ++ (show ansA)
+     putStrLn $ "day6b: " ++ (show ansB)
+
+match :: (Ord a, Eq a) => [a] -> [a] -> [a]
+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