From 1425c6c51d7cb5b6906aa0061f9c191b4322825a Mon Sep 17 00:00:00 2001
From: Kiana Sheibani <kiana.a.sheibani@gmail.com>
Date: Mon, 2 Dec 2024 17:05:34 -0500
Subject: [PATCH] feat: part 1-2

---
 advent-of-code-2024.ipkg |  3 +--
 src/AllDays.idr          |  1 +
 src/Day1/Part1.idr       |  1 +
 src/Day1/Part2.idr       | 31 +++++++++++++++++++++++++++++++
 src/Main.idr             |  3 +--
 5 files changed, 35 insertions(+), 4 deletions(-)
 create mode 100644 src/Day1/Part2.idr

diff --git a/advent-of-code-2024.ipkg b/advent-of-code-2024.ipkg
index 37257e6..03eb6b3 100644
--- a/advent-of-code-2024.ipkg
+++ b/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
diff --git a/src/AllDays.idr b/src/AllDays.idr
index 01e67ea..c384c4b 100644
--- a/src/AllDays.idr
+++ b/src/AllDays.idr
@@ -1,3 +1,4 @@
 module AllDays
 
 import public Day1.Part1
+import public Day1.Part2
diff --git a/src/Day1/Part1.idr b/src/Day1/Part1.idr
index b10eb4f..1116820 100644
--- a/src/Day1/Part1.idr
+++ b/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
 
diff --git a/src/Day1/Part2.idr b/src/Day1/Part2.idr
new file mode 100644
index 0000000..083d0d7
--- /dev/null
+++ b/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
diff --git a/src/Main.idr b/src/Main.idr
index 9cc0eb4..9cb5f9c 100644
--- a/src/Main.idr
+++ b/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)