2021.01

.tool-versions

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+erlang 23.2.3
+elixir 1.11.3-otp-23

challenges/2021/01.exs

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+Code.compile_file("./utils/utils.exs")
+
+defmodule Challenge do
+  @moduledoc false
+
+  def input do
+    Utils.load_input(__ENV__.file)
+  end
+
+  def first_result do
+    input()
+    |> Enum.reduce([0, nil], fn val, [sum, prev] ->
+      val = String.to_integer(val)
+
+      if prev && prev < val, do: [sum + 1, val], else: [sum, val]
+    end)
+    |> List.first()
+  end
+
+  def second_result do
+    input()
+    |> Enum.reduce([0, nil, nil, nil], fn val, [sum, prev3, prev2, prev1] = acc ->
+      val = String.to_integer(val)
+
+      if Enum.all?(acc) && prev3 < val do
+        [sum + 1, prev2, prev1, val]
+      else
+        [sum, prev2, prev1, val]
+      end
+    end)
+    |> List.first()
+  end
+end
+
+IO.inspect(Challenge.first_result(), label: "Q1")
+IO.inspect(Challenge.second_result(), label: "Q2")