diff --git a/README.md b/README.md
index 74da45b7..9d774b8a 100644
--- a/README.md
+++ b/README.md
@@ -588,3 +588,4 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 513. Find Bottom Left Tree Value                                | [Link](https://leetcode.com/problems/find-bottom-left-tree-value/)                                | [Link](./lib/medium/513_find_bottom_left_tree_value.rb)                                | [Link](./test/medium/test_513_find_bottom_left_tree_value.rb)                                |
 | 515. Find Largest Value in Each Tree Row                        | [Link](https://leetcode.com/problems/find-largest-value-in-each-tree-row/)                        | [Link](./lib/medium/515_find_largest_value_in_each_tree_row.rb)                        | [Link](./test/medium/test_515_find_largest_value_in_each_tree_row.rb)                        |
 | 516. Longest Palindromic Subsequence                            | [Link](https://leetcode.com/problems/longest-palindromic-subsequence/)                            | [Link](./lib/medium/516_longest_palindromic_subsequence.rb)                            | [Link](./test/medium/test_516_longest_palindromic_subsequence.rb)                            |
+| 523. Continuous Subarray Sum                                    | [Link](https://leetcode.com/problems/continuous-subarray-sum/)                                    | [Link](./lib/medium/523_continuous_subarray_sum.rb)                                    | [Link](./test/medium/test_523_continuous_subarray_sum.rb)                                    |
diff --git a/leetcode-ruby.gemspec b/leetcode-ruby.gemspec
index a4e02750..6d531ed1 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 = '7.2.2'
+  s.version = '7.2.3'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'
diff --git a/lib/medium/523_continuous_subarray_sum.rb b/lib/medium/523_continuous_subarray_sum.rb
new file mode 100644
index 00000000..88c58a86
--- /dev/null
+++ b/lib/medium/523_continuous_subarray_sum.rb
@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/continuous-subarray-sum/
+# @param {Integer[]} nums
+# @param {Integer} k
+# @return {Boolean}
+def check_subarray_sum(nums, k)
+  sum = 0
+  seen = ::Set.new
+  nums.each do |num|
+    rem = (sum + num) % k
+
+    return true if seen.include?(rem)
+
+    seen << sum
+    sum = rem
+  end
+
+  false
+end
diff --git a/test/medium/test_523_continuous_subarray_sum.rb b/test/medium/test_523_continuous_subarray_sum.rb
new file mode 100644
index 00000000..c7ecec2a
--- /dev/null
+++ b/test/medium/test_523_continuous_subarray_sum.rb
@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/523_continuous_subarray_sum'
+require 'minitest/autorun'
+
+class ContinuousSubarraySumTest < ::Minitest::Test
+  def test_default_one
+    assert(
+      check_subarray_sum(
+        [23, 2, 4, 6, 7],
+        6
+      )
+    )
+  end
+
+  def test_default_two
+    assert(
+      check_subarray_sum(
+        [23, 2, 6, 4, 7],
+        6
+      )
+    )
+  end
+
+  def test_default_three
+    assert(
+      !check_subarray_sum(
+        [23, 2, 6, 4, 7],
+        13
+      )
+    )
+  end
+end