diff --git a/README.md b/README.md
index 50f6e04f..964ad275 100644
--- a/README.md
+++ b/README.md
@@ -628,6 +628,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 841. Keys and Rooms                                             | [Link](https://leetcode.com/problems/keys-and-rooms/)                                             | [Link](./lib/medium/841_keys_and_rooms.rb)                                             | [Link](./test/medium/test_841_keys_and_rooms.rb)                                             |
 | 852. Peak Index in a Mountain Array                             | [Link](https://leetcode.com/problems/peak-index-in-a-mountain-array/)                             | [Link](./lib/medium/852_peak_index_in_a_mountain_array.rb)                             | [Link](./test/medium/test_852_peak_index_in_a_mountain_array.rb)                             |
 | 856. Score of Parentheses                                       | [Link](https://leetcode.com/problems/score-of-parentheses/)                                       | [Link](./lib/medium/856_score_of_parentheses.rb)                                       | [Link](./test/medium/test_856_score_of_parentheses.rb)                                       |
+| 858. Mirror Reflection                                          | [Link](https://leetcode.com/problems/mirror-reflection/)                                          | [Link](./lib/medium/858_mirror_reflection.rb)                                          | [Link](./test/medium/test_858_mirror_reflection.rb)                                          |
 
 ### Hard
 
diff --git a/leetcode-ruby.gemspec b/leetcode-ruby.gemspec
index 66b8a700..e8ea5b15 100644
--- a/leetcode-ruby.gemspec
+++ b/leetcode-ruby.gemspec
@@ -5,7 +5,7 @@ require 'English'
 ::Gem::Specification.new do |s|
   s.required_ruby_version = '>= 3.0'
   s.name = 'leetcode-ruby'
-  s.version = '7.6.9'
+  s.version = '7.7.0'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'
diff --git a/lib/medium/858_mirror_reflection.rb b/lib/medium/858_mirror_reflection.rb
new file mode 100644
index 00000000..96c92e21
--- /dev/null
+++ b/lib/medium/858_mirror_reflection.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/mirror-reflection/
+# @param {Integer} p
+# @param {Integer} q
+# @return {Integer}
+def mirror_reflection(p, q)
+  while p.even? && q.even?
+    p >>= 1
+    q >>= 1
+  end
+
+  1 - p % 2 + q % 2
+end
diff --git a/test/medium/test_858_mirror_reflection.rb b/test/medium/test_858_mirror_reflection.rb
new file mode 100644
index 00000000..236c4cf3
--- /dev/null
+++ b/test/medium/test_858_mirror_reflection.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/858_mirror_reflection'
+require 'minitest/autorun'
+
+class MirrorReflectionTest < ::Minitest::Test
+  def test_default_one = assert_equal(2, mirror_reflection(2, 1))
+
+  def test_default_two = assert_equal(1, mirror_reflection(3, 1))
+
+  def test_additional_one = assert_equal(1, mirror_reflection(2, 2))
+end