From 0849c576fd9f0bc420709979edc24f62ca8efad7 Mon Sep 17 00:00:00 2001
From: "exercism-solutions-syncer[bot]"
 <211797793+exercism-solutions-syncer[bot]@users.noreply.github.com>
Date: Wed, 6 Aug 2025 12:27:42 +0000
Subject: [PATCH] [Sync Iteration] elixir/run-length-encoding/1

---
 .../1/lib/run_length_encoder.ex               | 26 +++++++++++++++++++
 1 file changed, 26 insertions(+)
 create mode 100644 solutions/elixir/run-length-encoding/1/lib/run_length_encoder.ex

diff --git a/solutions/elixir/run-length-encoding/1/lib/run_length_encoder.ex b/solutions/elixir/run-length-encoding/1/lib/run_length_encoder.ex
new file mode 100644
index 0000000..d250db7
--- /dev/null
+++ b/solutions/elixir/run-length-encoding/1/lib/run_length_encoder.ex
@@ -0,0 +1,26 @@
+defmodule RunLengthEncoder do
+  @doc """
+  Generates a string where consecutive elements are represented as a data value and count.
+  "AABBBCCCC" => "2A3B4C"
+  For this example, assume all input are strings, that are all uppercase letters.
+  It should also be able to reconstruct the data into its original form.
+  "2A3B4C" => "AABBBCCCC"
+  """
+  @spec encode(String.t()) :: String.t()
+  def encode(string) do
+    Regex.scan(~r/(.)\1*/, string)
+    |> Enum.map_join(fn
+      [letter, letter] -> letter
+      [match, letter] -> "#{byte_size(match)}" <> letter
+    end)
+  end
+
+  @spec decode(String.t()) :: String.t()
+  def decode(string) do
+    Regex.scan(~r/([0-9]*)(.)/, string)
+    |> Enum.map_join(fn
+      [_, "", letter] -> letter
+      [_, count, letter] -> String.duplicate(letter, String.to_integer(count))
+    end)
+  end
+end