feat: part 1-2

advent-of-code-2024.ipkg

@@ -14,5 +14,4 @@ executable = advent-of-code-2024
 main = Main
 modules = Main, Utils, AllDays,
           Data.Problem,
-          Day1.Part1
+          Day1.Part1, Day1.Part2
-

src/AllDays.idr

@@ -1,3 +1,4 @@
 module AllDays
 
 import public Day1.Part1
+import public Day1.Part2

src/Day1/Part1.idr

@@ -16,6 +16,7 @@ parseLine str =
       | _ => Nothing
   in (,) <$> parseNat n1 <*> parseNat n2
 
+export
 parseInput : String -> Maybe (List Nat, List Nat)
 parseInput = map unzip . traverse parseLine . lines
 

src/Day1/Part2.idr

@@ -0,0 +1,31 @@
+module Day1.Part2
+
+import Data.Maybe
+import Data.SortedMap
+
+import Day1.Part1
+
+%default total
+
+--- DATA
+
+process : (left, right : List Nat) -> Nat
+process = go Z empty
+  where
+    go : (out : Nat) -> (cache : SortedMap Nat Nat)
+          -> (left, right : List Nat) -> Nat
+    go out _ [] _ = out
+    go out cache (n :: left) right =
+      let cached = lookup n cache
+          score = case cached of
+            Just c => c
+            Nothing => n * count (==n) right
+      in go (score + out) (if isJust cached
+                                then cache
+                                else insert n score cache) left right
+
+--- SOLUTION
+
+export
+solution : String -> Maybe Nat
+solution = map (uncurry process) . parseInput

src/Main.idr

@@ -1,7 +1,6 @@
 module Main
 
 import Data.List1
-import Data.Maybe
 import Data.String
 import Data.SortedMap
 import Data.SortedMap.Dependent
@@ -17,7 +16,7 @@ import AllDays
 ||| The latest problem that has been solved.
 -- NOTE: UPDATE AFTER EACH SOLUTION
 latest : Problem
-latest = Pr 1 Part1
+latest = Pr 1 Part2
 
 
 solMap : SortedMap Problem (String -> String)