diff --git a/README.md b/README.md
index c02d930e..f1f3666e 100644
--- a/README.md
+++ b/README.md
@@ -616,3 +616,4 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 713. Subarray Product Less Than K                               | [Link](https://leetcode.com/problems/subarray-product-less-than-k/)                               | [Link](./lib/medium/713_subarray_product_less_than_k.rb)                               | [Link](./test/medium/test_713_subarray_product_less_than_k.rb)                               |
 | 720. Longest Word in Dictionary                                 | [Link](https://leetcode.com/problems/longest-word-in-dictionary/)                                 | [Link](./lib/medium/720_longest_word_in_dictionary.rb)                                 | [Link](./test/medium/test_720_longest_word_in_dictionary.rb)                                 |
 | 725. Split Linked List in Parts                                 | [Link](https://leetcode.com/problems/split-linked-list-in-parts/)                                 | [Link](./lib/medium/725_split_linked_list_in_parts.rb)                                 | [Link](./test/medium/test_725_split_linked_list_in_parts.rb)                                 |
+| 729. My Calendar I                                              | [Link](https://leetcode.com/problems/my-calendar-i/)                                              | [Link](./lib/medium/729_my_calendar_i.rb)                                              | [Link](./test/medium/test_729_my_calendar_i.rb)                                              |
diff --git a/leetcode-ruby.gemspec b/leetcode-ruby.gemspec
index 882b5463..9eb0a6b0 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 = '7.5.1.1'
+  s.version = '7.5.2'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'
diff --git a/lib/medium/729_my_calendar_i.rb b/lib/medium/729_my_calendar_i.rb
new file mode 100644
index 00000000..0778634d
--- /dev/null
+++ b/lib/medium/729_my_calendar_i.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/my-calendar-i/
+class MyCalendar
+  # Init
+  def initialize
+    @calendar = []
+  end
+
+  # @param {Integer} start_time
+  # @param {Integer} end_time
+  # @return {Boolean}
+  def book(start_time, end_time)
+    @calendar.each { |iv| return false if iv[0] < end_time && iv[1] > start_time }
+
+    @calendar << [start_time, end_time]
+
+    true
+  end
+end
diff --git a/test/medium/test_729_my_calendar_i.rb b/test/medium/test_729_my_calendar_i.rb
new file mode 100644
index 00000000..95f99d37
--- /dev/null
+++ b/test/medium/test_729_my_calendar_i.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/729_my_calendar_i'
+require 'minitest/autorun'
+
+class MyCalendarITest < ::Minitest::Test
+  def test_default_one
+    my_calendar = ::MyCalendar.new
+
+    assert(my_calendar.book(10, 20))
+    assert(!my_calendar.book(15, 25))
+    assert(my_calendar.book(20, 30))
+  end
+end