Day 3 (regex go brrrrrr)

Also some housekeeping

aoc2024.cabal

@@ -14,8 +14,10 @@ common warnings
 
 library
     import:           warnings
-    exposed-modules:  Day1, Day2
+    exposed-modules:  Day1, Day2, Day3
     build-depends: base ^>=4.18.0.0
+                 , regex
+                 , array
     hs-source-dirs:   src
     default-language: GHC2021
 

run/Main.hs

@@ -1,10 +1,13 @@
 module Main where
 import qualified Day1 as D1
 import qualified Day2 as D2
+import qualified Day3 as D3
 
 solutions :: [(String -> String, String -> String)]
-solutions = [(D1.part1, D1.part2),
-             (D2.part1, D2.part2)]
+solutions = [ (D1.part1, D1.part2)
+            , (D2.part1, D2.part2)
+            , (D3.part1, D3.part2)
+            ]
 
 
 run :: Int -> Int -> IO () 

src/Day3.hs

@@ -0,0 +1,34 @@
+{-# LANGUAGE QuasiQuotes #-}
+module Day3 (part1, part2) where
+
+import Text.RE.TDFA.String
+import Text.RE.Replace
+import Data.Array
+
+part1 :: String -> String
+part1 = show
+      . sum
+      . map (\x ->
+               (read $ capturedText $ x ! 1 :: Integer)
+               * (read $ capturedText $ x ! 2 :: Integer)
+            )
+      . map matchArray
+      . allMatches
+      . (*=~ [re|mul\(([0-9]{1,3}),([0-9]{1,3})\)|])
+
+
+
+part2 :: String -> String
+part2 = show
+        . snd
+        . foldl (\(on, acc) new ->
+                   case head new of
+                     "do()" -> (True, acc)
+                     "don't()" -> (False, acc)
+                     _ -> if not on then (on, acc) else
+                       (on, acc + (read $ new !! 2 :: Integer) * (read $ new !! 3 :: Integer))
+                ) (True, 0)
+        . map (map capturedText . elems)
+        . map matchArray
+        . allMatches
+        . (*=~ [re|(do\(\)|don't\(\)|mul\(([0-9]{1,3}),([0-9]{1,3})\))|])

test/3.1

@@ -0,0 +1 @@
+xmul(2,4)%&mul[3,7]!@^do_not_mul(5,5)+mul(32,64]then(mul(11,8)mul(8,5))

test/3.2

@@ -0,0 +1 @@
+xmul(2,4)&mul[3,7]!^don't()_mul(5,5)+mul(32,64](mul(11,8)undo()?mul(8,5))

test/Main.hs

@@ -2,19 +2,29 @@ module Main (main) where
 import Test.Hspec
 import Day1
 import Day2
+import Day3
 
 main :: IO ()
 main = do
-  day1in <- readFile "test/1.testcase"
-  day2in <- readFile "test/2.testcase"
   hspec $ do
     describe "Day1" $ do
       it "solves part 1" $ do
-        Day1.part1 day1in `shouldBe` "11"
+        input <- readFile "test/1"
+        Day1.part1 input `shouldBe` "11"
       it "solves part 2" $ do
-        Day1.part2 day1in `shouldBe` "31"
+        input <- readFile "test/1"
+        Day1.part2 input `shouldBe` "31"
     describe "Day 2" $ do
       it "solves part 1" $ do
-        Day2.part1 day2in `shouldBe` "2"
+        input <- readFile "test/2"
+        Day2.part1 input `shouldBe` "2"
       it "solves part 2" $ do
-        Day2.part2 day2in `shouldBe` "4"
+        input <- readFile "test/2"
+        Day2.part2 input `shouldBe` "4"
+    describe "Day 3" $ do
+      it "solves part 1" $ do
+        input <- readFile "test/3.1"
+        Day3.part1 input `shouldBe` "161"
+      it "solves part 2" $ do
+        input <- readFile "test/3.2"
+        Day3.part2 input `shouldBe` "48"