Add Elixir benchmarker

challenges/2021/01.exs

@@ -28,5 +28,5 @@ defmodule Challenge do
   end
 end
 
-Utils.execute(&Challenge.first_result/1, __ENV__.file, "Q1")
-Utils.execute(&Challenge.second_result/1, __ENV__.file, "Q2")
+Utils.run(&Challenge.first_result/1, __ENV__.file, "Q1")
+Utils.run(&Challenge.second_result/1, __ENV__.file, "Q2")

challenges/2021/02.exs

@@ -0,0 +1,20 @@
+Code.compile_file(Path.join([__ENV__.file], ["../../../utils/utils.exs"]))
+
+defmodule Challenge do
+  @moduledoc false
+
+  def input do
+    Utils.load_input(__ENV__.file)
+  end
+
+  def first_result(input) do
+    input
+  end
+
+  def second_result(input) do
+    input
+  end
+end
+
+Utils.run(&Challenge.first_result/1, __ENV__.file, "Q1")
+Utils.run(&Challenge.second_result/1, __ENV__.file, "Q2")

challenges/2021/template.exs

@@ -3,10 +3,6 @@ Code.compile_file(Path.join([__ENV__.file], ["../../../utils/utils.exs"]))
 defmodule Challenge do
   @moduledoc false
 
-  def input do
-    Utils.load_input(__ENV__.file)
-  end
-
   def first_result(input) do
     input
   end
@@ -16,5 +12,5 @@ defmodule Challenge do
   end
 end
 
-Utils.execute(&Challenge.first_result/1, __ENV__.file, "Q1")
-Utils.execute(&Challenge.second_result/1, __ENV__.file, "Q2")
+Utils.run(&Challenge.first_result/1, __ENV__.file, "Q1")
+Utils.run(&Challenge.second_result/1, __ENV__.file, "Q2")

utils/utils.exs

@@ -10,6 +10,18 @@ defmodule Utils do
     |> String.split("\n")
   end
 
+  def run(function, file, label) do
+    args = System.argv()
+
+    if "-b" in args do
+      times_index = Enum.find_index(args, &(&1 == "-b")) + 1
+      times = args |> Enum.at(times_index, "20") |> String.to_integer()
+      benchmark(function, file, label, times)
+    else
+      execute(function, file, label)
+    end
+  end
+
   def execute(function, file, label) do
     input = load_input(file)
 
@@ -18,6 +30,29 @@ defmodule Utils do
     |> log_result(label)
   end
 
+  def benchmark(function, file, label, times) do
+    input = load_input(file)
+
+    average_time =
+      1..times
+      |> Enum.map(fn _ ->
+        fn -> function.(input) end
+        |> :timer.tc()
+        |> elem(0)
+        |> Kernel./(1_000)
+      end)
+      |> Enum.reduce(
+        [nil, 0],
+        fn
+          val, [nil, 0] -> [val, 1]
+          val, [avg, count] -> [(avg * count + val) / (count + 1), count + 1]
+        end
+      )
+      |> List.first()
+
+    IO.puts("#{label} ran #{times} times with an average of #{average_time}ms")
+  end
+
   defp log_result({time, result}, label) do
     IO.inspect(result, label: label)
     IO.puts("#{label} completed in #{time / 1_000}ms")