feat: part 3-1

advent-of-code-2024.ipkg

@@ -9,10 +9,12 @@ license = "MIT"
 sourcedir = "src"
 
 langversion >= 0.6.0
+depends = contrib
 
 executable = advent-of-code-2024
 main = Main
 modules = Main, Utils, AllDays,
           Data.Problem,
           Day1.Part1, Day1.Part2,
-          Day2.Part1, Day2.Part2
+          Day2.Part1, Day2.Part2,
+          Day3.Part1

src/AllDays.idr

@@ -4,3 +4,4 @@ import public Day1.Part1
 import public Day1.Part2
 import public Day2.Part1
 import public Day2.Part2
+import public Day3.Part1

src/Day3/Part1.idr

@@ -0,0 +1,29 @@
+module Day3.Part1
+
+import Data.Either
+import Data.Maybe
+import Data.String
+import Data.String.Parser
+
+--- PARSING
+
+export
+scan : Monad m => ParseT m a -> ParseT m a
+scan p = many (requireFailure p *> skip (satisfy (const True))) *> p
+
+export
+mul : Parser Integer
+mul = do
+  skip $ string "mul("
+  x <- integer
+  skip $ string ","
+  y <- integer
+  skip $ string ")"
+  pure $ x * y
+
+--- SOLUTION
+
+export
+solution : String -> Integer
+solution = fromMaybe 0 . map (sum . fst) . eitherToMaybe .
+            parse (many $ scan mul)

src/Main.idr

@@ -14,7 +14,7 @@ import AllDays
 ||| The latest problem that has been solved.
 -- NOTE: UPDATE AFTER EACH SOLUTION
 latest : Problem
-latest = Pr 2 Part2
+latest = Pr 3 Part1
 
 
 solMap : SortedMap Problem (String -> String)