fix: part 1 day09

lib/aoc_elixir/solutions/y25/day09.ex

@@ -0,0 +1,47 @@
+defmodule AocElixir.Solutions.Y25.Day09 do
+  alias AoC.Input
+
+  def parse(input, _part) do
+    Input.stream_file_lines(input, trim: true)
+    |> Stream.map(&(String.split(&1, ",") |> Enum.map(fn v -> v |> String.to_integer() end)))
+  end
+
+  def part_one(problem) do
+    # {[min_x, _], [max_x, _]} =
+    #   problem
+    #   |> Enum.min_max_by(fn v -> Enum.at(v, 0) end)
+    # {[_, min_y], [_, max_y]} =
+    #   problem
+    #   |> Enum.min_max_by(fn v -> Enum.at(v, 1) end)
+
+    problem
+    # |> Enum.filter(fn [px, py] ->
+    #   px == min_x or py == min_y or px == max_x or py == max_y
+    # end)
+    |> unique_pairs(&area/1)
+    # |> IO.inspect(label: "pairs", charlists: false)
+    |> Enum.max_by(&elem(&1, 1))
+    |> elem(1)
+  end
+
+  defp area({[ax, ay], [bx, by]}) do
+    (abs(bx - ax) + 1) * (abs(ay - by) + 1)
+  end
+
+  def unique_pairs(list, func) do
+    list
+    |> Enum.with_index()
+    |> Enum.flat_map(fn {a, i} ->
+      list
+      |> Enum.drop(i + 1)
+      |> Enum.map(fn b ->
+        couple = {a, b}
+        {couple, func.(couple)}
+      end)
+    end)
+  end
+
+  # def part_two(problem) do
+  #   problem
+  # end
+end

test/2025/day09_test.exs

@@ -0,0 +1,56 @@
+defmodule AocElixir.Solutions.Y25.Day09Test do
+  alias AoC.Input, warn: false
+  alias AocElixir.Solutions.Y25.Day09, as: Solution, warn: false
+  use ExUnit.Case, async: true
+
+  defp solve(input, part) do
+    problem =
+      input
+      |> Input.as_file()
+      |> Solution.parse(part)
+
+    apply(Solution, part, [problem])
+  end
+
+  test "part one example" do
+    input = ~S"""
+    7,1
+    11,1
+    11,7
+    9,7
+    9,5
+    2,5
+    2,3
+    7,3
+    """
+
+    assert 50 == solve(input, :part_one)
+  end
+
+  @part_one_solution 4_755_429_952
+  @tag :solution
+  test "part one solution" do
+    assert {:ok, @part_one_solution} == AoC.run(2025, 9, :part_one)
+  end
+
+  # test "part two example" do
+  #   input = ~S"""
+  #   7,1
+  #   11,1
+  #   11,7
+  #   9,7
+  #   9,5
+  #   2,5
+  #   2,3
+  #   7,3
+  #   """
+  #
+  #   assert 24 == solve(input, :part_two)
+  # end
+
+  # @part_two_solution CHANGE_ME
+  #
+  # test "part two solution" do
+  #   assert {:ok, @part_two_solution} == AoC.run(2025, 9, :part_two)
+  # end
+end