day 3

3/solution.hs

@@ -0,0 +1,24 @@
+import Data.List
+import Text.Regex
+
+solve1 :: String -> Int -> Int
+solve1 string curr = 
+    case matchRegexAll (mkRegex "mul\\(([1-9][0-9]?[0-9]?),([1-9][0-9]?[0-9]?)\\)") string of
+        Nothing -> curr
+        Just (_, _, rem, matched) -> solve1 (rem) (curr + (foldl (*) 1 (map read matched)))
+
+solve2 :: String -> Int -> Bool -> Int
+solve2 string curr status = 
+    case matchRegexAll (mkRegex "mul\\(([1-9][0-9]?[0-9]?),([1-9][0-9]?[0-9]?)\\)|(do\\(\\))|(don't\\(\\))") string of
+        Nothing -> curr
+        Just (_, _, rem, [_, _, "do()", _]) -> solve2 (rem) curr True
+        Just (_, _, rem, [_, _, _, "don't()"]) -> solve2 (rem) curr False
+        Just (_, _, rem, matched) -> solve2 (rem) (curr + (if status then (foldl (*) 1 (map read (take 2 matched))) else 0)) status
+
+main :: IO()
+main = do
+       fileinp <- readFile "input.txt"
+       let solved1 = solve1 fileinp 0
+       let solved2 = solve2 fileinp 0 True
+       print solved1
+       print solved2