From b5ea05b3ffa77daa32584b263fdec134f2783fa7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C5=81ukasz=20Niemier?= <~@hauleth.dev>
Date: Mon, 1 Dec 2025 11:21:21 +0100
Subject: [PATCH] Day 3 of 2025

---
 2025/day02.livemd |  2 +-
 2025/day03.livemd | 52 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 53 insertions(+), 1 deletion(-)
 create mode 100644 2025/day03.livemd

diff --git a/2025/day02.livemd b/2025/day02.livemd
index ca85efd..e52d040 100644
--- a/2025/day02.livemd
+++ b/2025/day02.livemd
@@ -77,4 +77,4 @@ ranges
 |> Enum.sum()
 ```
 
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diff --git a/2025/day03.livemd b/2025/day03.livemd
new file mode 100644
index 0000000..0f5247c
--- /dev/null
+++ b/2025/day03.livemd
@@ -0,0 +1,52 @@
+# Day 03
+
+```elixir
+Mix.install([:kino_aoc])
+```
+
+## Section
+
+<!-- livebook:{"attrs":"eyJhc3NpZ25fdG8iOiJwdXp6bGVfaW5wdXQiLCJkYXkiOiIzIiwic2Vzc2lvbl9zZWNyZXQiOiJBRFZFTlRfT0ZfQ09ERV9TRVNTSU9OIiwieWVhciI6IjIwMjUifQ","chunks":null,"kind":"Elixir.KinoAOC.HelperCell","livebook_object":"smart_cell"} -->
+
+```elixir
+{:ok, puzzle_input} =
+  KinoAOC.download_puzzle("2025", "3", System.fetch_env!("LB_ADVENT_OF_CODE_SESSION"))
+```
+
+```elixir
+batteries =
+  puzzle_input
+  |> String.split("\n", trim: true)
+  |> Enum.map(fn row ->
+    row
+    |> String.to_charlist()
+    |> Enum.map(& &1 - ?0)
+  end)
+```
+
+```elixir
+defmodule Joltage do
+  def make_largest(list, n) do
+    to_remove = length(list) - n
+    Enum.reduce(1..to_remove, list, fn _, acc -> make_larger(acc) end)
+  end
+  
+  def make_larger([_]), do: []
+  def make_larger([a, b | rest]) when a < b, do: [b | rest]
+  def make_larger([b | rest]), do: [b | make_larger(rest)]
+end
+```
+
+## Part 1
+
+```elixir
+Enum.sum_by(batteries, &Integer.undigits(Joltage.make_largest(&1, 2)))
+```
+
+## Part 2
+
+```elixir
+Enum.sum_by(batteries, &Integer.undigits(Joltage.make_largest(&1, 12)))
+```
+
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-- 
2.51.2