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+defmodule Day02 do
+ def part_one(data) do
+ data
+ |> Enum.reduce(%{pos: 0, dep: 0}, &method_one/2)
+ |> get_answer()
+ end
+
+ def part_two(data) do
+ data
+ |> Enum.reduce(%{pos: 0, dep: 0, aim: 0}, &method_two/2)
+ |> get_answer()
+ end
+
+ defp method_one({:forward, x}, s), do: %{s | pos: s.pos + x}
+ defp method_one({:up, x}, s), do: %{s | dep: s.dep - x}
+ defp method_one({:down, x}, s), do: %{s | dep: s.dep + x}
+
+ defp method_two({:forward, x}, s), do: %{s | pos: s.pos + x, dep: s.dep + s.aim * x}
+ defp method_two({:up, x}, s), do: %{s | aim: s.aim - x}
+ defp method_two({:down, x}, s), do: %{s | aim: s.aim + x}
+
+ defp get_answer(s), do: s.pos * s.dep
+end
+
+data =
+ File.read!("day-02/input.txt")
+ |> String.split("\n", trim: true)
+ |> Enum.map(&String.split/1)
+ |> Enum.map(fn [dir, amt] -> {String.to_atom(dir), String.to_integer(amt)} end)
+
+Day02.part_one(data) |> IO.inspect()
+Day02.part_two(data) |> IO.inspect()