day 1 part 1

.tool-versions

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+erlang 26.1.1
+elixir 1.15.6-otp-26

day1.ex

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+defmodule Excersize1 do
+  def to_command(s) do
+    try do
+      {:add, s |> String.trim() |> String.to_integer()}
+    rescue 
+      ArgumentError -> {:reset}
+    end
+  end
+
+  def init_state() do
+    {nil, 0, false}
+  end
+  def apply_command(command, state) do
+    case command do
+      {:add, n} -> apply_add(n, state)
+      {:reset} -> apply_reset(state)
+    end
+  end
+
+  defp apply_add(n, state) do
+    {current, total, exit} = state
+    new_current = if is_nil(current) do 0 else current end + n
+    {new_current, max(total, new_current), exit}
+  end
+
+  defp apply_reset(state) do
+    {current, total, exit} = state
+    case current do
+      nil -> {current, total, true}
+      _ -> {nil, total, exit}
+    end
+  end
+end
+
+result = IO.stream() |> 
+  Enum.reduce_while(
+    Excersize1.init_state(),
+    fn line, acc -> line
+      |> Excersize1.to_command()
+      |> Excersize1.apply_command(acc)
+      |> then(fn acc -> if elem(acc, 2) do {:halt, acc} else {:cont, acc} end end)
+    end
+  )
+
+  IO.puts(elem(result, 1))