From 4122946ece9f6d2b40c591dae6fadbcdaa4dbf64 Mon Sep 17 00:00:00 2001
From: Max Duval <max.duval@hometrack.com>
Date: Wed, 3 Dec 2025 17:48:08 +0000
Subject: [PATCH] feat: day 3 part 2 joltage working for test

but not actually working
---
 src/solve_2025_03.gleam | 59 ++++++++++++++++++++++++++++++++++++++++-
 test/test_2025_03.gleam |  2 +-
 2 files changed, 59 insertions(+), 2 deletions(-)

diff --git a/src/solve_2025_03.gleam b/src/solve_2025_03.gleam
index a702a08..11ada05 100644
--- a/src/solve_2025_03.gleam
+++ b/src/solve_2025_03.gleam
@@ -1,5 +1,6 @@
 import gleam/int
 import gleam/list
+import gleam/order
 import gleam/string
 
 pub fn part_one(input: String) -> Int {
@@ -19,8 +20,64 @@ pub fn part_one(input: String) -> Int {
   accumulator + tens * 10 + ones
 }
 
+type Battery {
+  Battery(joltage: Int, index: Int)
+}
+
 pub fn part_two(input: String) -> Int {
-  -1
+  use accumulator, digits <- list.fold(parse(input), 0)
+
+  let sorted =
+    digits
+    |> list.index_map(Battery)
+    |> list.sort(fn(left, right) {
+      order.break_tie(
+        in: int.compare(right.joltage, left.joltage),
+        with: int.compare(left.index, right.index),
+      )
+    })
+  // |> echo
+
+  let added =
+    filler([], sorted, 12, list.length(sorted))
+    |> echo
+    |> list.fold(0, fn(accumulator, battery) {
+      accumulator * 10 + battery.joltage
+    })
+    |> echo
+
+  accumulator + added
+}
+
+fn filler(
+  so_far: List(Battery),
+  left_to_check: List(Battery),
+  banks_to_fill: Int,
+  length: Int,
+) -> List(Battery) {
+  case banks_to_fill {
+    0 -> so_far
+    _ -> {
+      case
+        left_to_check
+        |> list.find(fn(battery) { battery.index + banks_to_fill <= length })
+      {
+        Ok(battery) -> {
+          let left_to_check =
+            list.filter(left_to_check, fn(b) { b.index > battery.index })
+          echo #(battery, banks_to_fill - 1, length, so_far)
+          echo left_to_check
+          filler(
+            list.append(so_far, [battery]),
+            left_to_check,
+            banks_to_fill - 1,
+            length,
+          )
+        }
+        Error(_) -> []
+      }
+    }
+  }
 }
 
 fn parse(input: String) -> List(List(Int)) {
diff --git a/test/test_2025_03.gleam b/test/test_2025_03.gleam
index 569a5a9..e749556 100644
--- a/test/test_2025_03.gleam
+++ b/test/test_2025_03.gleam
@@ -21,5 +21,5 @@ pub fn part_two_test() {
     input
     |> string.trim
     |> solve_2025_03.part_two
-  assert result == -1
+  assert result == 3_121_910_778_619
 }
-- 
2.51.2