Add Elixir benchmark

elixir/.gitignore

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+# The directory Mix will write compiled artifacts to.
+/_build/
+
+# If you run "mix test --cover", coverage assets end up here.
+/cover/
+
+# The directory Mix downloads your dependencies sources to.
+/deps/
+
+# Where third-party dependencies like ExDoc output generated docs.
+/doc/
+
+# Ignore .fetch files in case you like to edit your project deps locally.
+/.fetch
+
+# If the VM crashes, it generates a dump, let's ignore it too.
+erl_crash.dump
+
+# Also ignore archive artifacts (built via "mix archive.build").
+*.ez
+
+# Ignore package tarball (built via "mix hex.build").
+elixir-*.tar
+

elixir/README.md

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+# Elixir
+
+Running it once will compile the app.
+
+## Compile
+```sh
+MIX_ENV=prod mix run lib/main.exs
+```
+
+## Execute
+```sh
+mix run lib/main.exs
+```

elixir/lib/bulk_ops.ex

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+defmodule BulkOps do
+  defmodule SplitResult do
+    defstruct [:lower, :equal, :greater]
+  end
+
+  def merge(nil, greater), do: greater
+  def merge(lower, nil), do: lower
+
+  def merge(lower, greater) do
+    if lower.y < greater.y do
+      %{lower | right: merge(lower.right, greater)}
+    else
+      %{greater | left: merge(lower, greater.left)}
+    end
+  end
+
+  def split_binary(nil, _value), do: {nil, nil}
+
+  def split_binary(orig, value) do
+    if orig.x < value do
+      {first, second} = split_binary(orig.right, value)
+      {%{orig | right: first}, second}
+    else
+      {first, second} = split_binary(orig.left, value)
+      {first, %{orig | left: second}}
+    end
+  end
+
+  def merge3(lower, equal, greater) do
+    merge(merge(lower, equal), greater)
+  end
+
+  def split(orig, value) do
+    {lower, equal_greater} = split_binary(orig, value)
+    {equal, greater} = split_binary(equal_greater, value + 1)
+    %SplitResult{lower: lower, equal: equal, greater: greater}
+  end
+end

elixir/lib/main.exs

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+{_cur, _root, res} =
+  Enum.reduce(1..1_000_000, {5, nil, 0}, fn i, acc ->
+    {cur, root, res} = acc
+    a = rem(i, 3)
+    cur = rem(cur * 57 + 43, 10007)
+
+    case a do
+      0 ->
+        root = Treap.insert(root, cur)
+        {cur, root, res}
+
+      1 ->
+        root = Treap.erase(root, cur)
+        {cur, root, res}
+
+      2 ->
+        {root, present} = Treap.has_value?(root, cur)
+        res = if present, do: res + 1, else: res
+        {cur, root, res}
+    end
+  end)
+
+IO.puts(res)

elixir/lib/treap.ex

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+defmodule Treap do
+  defmodule TreapNode do
+    defstruct [:x, :y, :left, :right]
+  end
+
+  def has_value?(root, x) do
+    splitted = BulkOps.split(root, x)
+    res = splitted.equal != nil
+    root = BulkOps.merge3(splitted.lower, splitted.equal, splitted.greater)
+    {root, res}
+  end
+
+  def insert(root, x) do
+    splitted = BulkOps.split(root, x)
+
+    if splitted.equal == nil do
+      BulkOps.merge3(splitted.lower, %TreapNode{x: x, y: :rand.uniform()}, splitted.greater)
+    else
+      BulkOps.merge3(splitted.lower, splitted.equal, splitted.greater)
+    end
+  end
+
+  def erase(root, x) do
+    splitted = BulkOps.split(root, x)
+    BulkOps.merge(splitted.lower, splitted.greater)
+  end
+end

elixir/mix.exs

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+defmodule Elixir.MixProject do
+  use Mix.Project
+
+  def project do
+    [
+      app: :elixir,
+      version: "0.1.0",
+      elixir: "~> 1.10",
+      start_permanent: Mix.env() == :prod,
+      deps: deps()
+    ]
+  end
+
+  # Run "mix help compile.app" to learn about applications.
+  def application do
+    []
+  end
+
+  # Run "mix help deps" to learn about dependencies.
+  defp deps do
+    [
+      # {:dep_from_hexpm, "~> 0.3.0"},
+      # {:dep_from_git, git: "https://github.com/elixir-lang/my_dep.git", tag: "0.1.0"}
+    ]
+  end
+end