Solve day 3

lib/aoc2024/day_03.ex

@@ -1,13 +1,26 @@
 defmodule Aoc2024.Day03 do
-  def parse(input) do
-    input |> String.split("\n", trim: true)
+  def part1(instructions) do
+    ~r/mul\(([0-9]+),([0-9]+)\)/
+    |> Regex.scan(instructions)
+    |> Enum.map(fn [_all, num1_str, num2_str] ->
+      case {Integer.parse(num1_str), Integer.parse(num2_str)} do
+        {{num1, ""}, {num2, ""}} -> num1 * num2
+        _ -> 0
+      end
+    end)
+    |> Enum.sum()
   end
 
-  def part1(_lines) do
-    :todo1
-  end
+  def part2(instructions) do
+    conditional_instructions =
+      ~r/don't\(\).*?do\(\)/s
+      |> Regex.replace(instructions, "|")
 
-  def part2(_lines) do
-    :todo2
+    # handle possible case where the instructions end with don't() and more mul
+    conditional_instructions2 =
+      ~r/don't\(\).*$/s
+      |> Regex.replace(conditional_instructions, "|")
+
+    part1(conditional_instructions2)
   end
 end