day 6

06/solution.hs

@@ -0,0 +1,52 @@
+import Debug.Trace
+import Data.Maybe
+import Data.List
+
+(***) :: (a -> a') -> (b -> b') -> (a, b) -> (a', b')
+(f *** g) (x, y) = (f x, g y)
+
+traceOut :: Show a => a -> a
+traceOut x = traceShow x x
+
+addFirst :: [[a]] -> a -> [[a]]
+addFirst [] x = [[x]]
+addFirst (y:ys) x = (x : y) : ys
+
+split :: Eq a => [a] -> [a] -> [[a]]
+split _ [] = []
+split delims (x:xs)
+  | x `elem` delims = [] : split delims xs
+  | otherwise       = addFirst (split delims xs) x
+
+data Symbol = Mul | Add
+
+instance Show Symbol where
+    show Mul = "*"
+    show Add = "+"
+
+toIdFunction :: Symbol -> (Int, (Int -> Int -> Int))
+toIdFunction Mul = (1, (*))
+toIdFunction Add = (0, (+))
+
+toSymbol :: Char -> Maybe Symbol
+toSymbol '*' = Just Mul
+toSymbol '+' = Just Add
+toSymbol _ = Nothing
+
+parseFile1 :: String -> ([Symbol], [[Int]])
+parseFile1 = (map (fromJust . toSymbol . head) *** (map (map read) . transpose)) . fromJust . uncons .  reverse . map words . lines
+
+solve :: ([Symbol], [[Int]]) -> Int
+solve = sum . map (uncurry $ uncurry $ flip foldl) . (uncurry zip) . (map toIdFunction *** id)
+
+parseFile2 :: String -> ([Symbol], [[Int]])
+parseFile2 = ((map (fromJust . toSymbol . head) . words) *** (map (map (read . reverse)) . split [""] . map (takeWhile (/= ' ') . dropWhile (== ' ')) . transpose)) . fromJust . uncons .  reverse . lines
+
+main = do 
+    fileinp <- readFile "input.txt"
+    let input1 = parseFile1 fileinp
+    let solved1 = solve input1
+    print solved1
+    let input2 = parseFile2 fileinp
+    let solved2 = solve input2
+    print solved2