day 19

19/solution.hs

@@ -0,0 +1,55 @@
+import Debug.Trace
+import Text.Regex
+import Data.List
+import qualified Data.List.Split as S
+
+import Data.Function.Memoize
+import Control.Parallel.Strategies
+
+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 :: [Char] -> String -> [String]
+split _ [] = []
+split delims (x:xs)
+  | elem x delims = [[]] ++ split delims xs
+  | otherwise     = addFirst (split delims xs) x
+
+splitInput :: String -> [String]
+splitInput = filter (/="") . split ", "
+
+splitInput2 :: String -> [String]
+splitInput2 = split "\n"
+
+solve1 :: [String] -> [String] -> Int
+solve1 patterns towels = length $ filter (match (mkRegex ("^(" ++ (concat $ intersperse "|" patterns) ++ ")*$"))) towels
+
+match :: Regex -> String -> Bool
+match regex str = case matchRegex regex str of
+    Just _ -> True
+    Nothing -> False
+
+solveTowel :: [String] -> String -> Int
+solveTowel patterns towel = sum $ ((map (
+        \pattern -> case matchRegexAll (mkRegex ('^':pattern)) towel of
+            Nothing -> 0
+            Just (_, _, remaining, _) -> if remaining == "" then 1 else (memoize2 solveTowel) patterns remaining
+    ) patterns) `using` parList rdeepseq)
+
+solve2 :: [String] -> [String] -> Int
+solve2 patterns towels = sum $ ((map ((memoize2 solveTowel) patterns) towels) `using` parList rdeepseq)
+
+main :: IO()
+main = do
+       fileinp <- readFile "input.txt"
+       let sections = S.splitOn "\n\n" fileinp
+       let parsed = splitInput (sections!!0)
+       let parsed2 = splitInput2 (sections!!1)
+       let solved1 = solve1 parsed parsed2
+       let solved2 = solve2 parsed parsed2
+       print solved1
+       print solved2