diff --git a/README.md b/README.md
index 3d7af9c7..289b84e0 100644
--- a/README.md
+++ b/README.md
@@ -700,6 +700,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 1472. Design Browser History                                                        | [Link](https://leetcode.com/problems/design-browser-history/)                                                        | [Link](./lib/medium/1472_design_browser_history.rb)                                                        | [Link](./test/medium/test_1472_design_browser_history.rb)                                                        |
 | 1481. Least Number of Unique Integers after K Removals                              | [Link](https://leetcode.com/problems/least-number-of-unique-integers-after-k-removals/)                              | [Link](./lib/medium/1481_least_number_of_unique_integers_after_k_removals.rb)                              | [Link](./test/medium/test_1481_least_number_of_unique_integers_after_k_removals.rb)                              |
 | 1492. The kth Factor of n                                                           | [Link](https://leetcode.com/problems/the-kth-factor-of-n/)                                                           | [Link](./lib/medium/1492_the_kth_factor_of_n.rb)                                                           | [Link](./test/medium/test_1492_the_kth_factor_of_n.rb)                                                           |
+| 1504. Count Submatrices With All Ones                                               | [Link](https://leetcode.com/problems/count-submatrices-with-all-ones/)                                               | [Link](./lib/medium/1504_count_submatrices_with_all_ones.rb)                                               | [Link](./test/medium/test_1504_count_submatrices_with_all_ones.rb)                                               |
 | 2116. Check if a Parentheses String Can Be Valid                                    | [Link](https://leetcode.com/problems/check-if-a-parentheses-string-can-be-valid/)                                    | [Link](./lib/medium/2116_check_if_a_parentheses_string_can_be_valid.rb)                                    | [Link](./test/medium/test_2116_check_if_a_parentheses_string_can_be_valid.rb)                                    |
 | 2425. Bitwise XOR of All Pairings                                                   | [Link](https://leetcode.com/problems/bitwise-xor-of-all-pairings/)                                                   | [Link](./lib/medium/2425_bitwise_xor_of_all_pairings.rb)                                                   | [Link](./test/medium/test_2425_bitwise_xor_of_all_pairings.rb)                                                   |
 | 2429. Minimize XOR                                                                  | [Link](https://leetcode.com/problems/minimize-xor/)                                                                  | [Link](./lib/medium/2429_minimize_xor.rb)                                                                  | [Link](./test/medium/test_2429_minimize_xor.rb)                                                                  |
diff --git a/leetcode-ruby.gemspec b/leetcode-ruby.gemspec
index b01d4c35..130a5a4e 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 = '8.6.6'
+  s.version = '8.6.7'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'
diff --git a/lib/medium/1504_count_submatrices_with_all_ones.rb b/lib/medium/1504_count_submatrices_with_all_ones.rb
new file mode 100644
index 00000000..c71a4362
--- /dev/null
+++ b/lib/medium/1504_count_submatrices_with_all_ones.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/count-submatrices-with-all-ones/
+# @param {Integer[][]} mat
+# @return {Integer}
+def num_submat(mat)
+  n = mat[0].length
+  result = 0
+  h = ::Array.new(n, 0)
+
+  mat.each do |sub|
+    f = [-1]
+    s = [0]
+
+    n.times { |j| h[j] = sub[j].zero? ? 0 : h[j] + 1 }
+
+    n.times do |j|
+      while f.first >= 0 && h[f.first] >= h[j]
+        f.shift
+        s.shift
+      end
+
+      sum = h[j] * (j - f.first) + s.first
+
+      f.unshift(j)
+      s.unshift(sum)
+
+      result += sum
+    end
+  end
+
+  result
+end
diff --git a/test/medium/test_1504_count_submatrices_with_all_ones.rb b/test/medium/test_1504_count_submatrices_with_all_ones.rb
new file mode 100644
index 00000000..65e9cfbd
--- /dev/null
+++ b/test/medium/test_1504_count_submatrices_with_all_ones.rb
@@ -0,0 +1,33 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/1504_count_submatrices_with_all_ones'
+require 'minitest/autorun'
+
+class CountSubmatricesWithAllOnesTest < ::Minitest::Test
+  def test_default_one
+    assert_equal(
+      13,
+      num_submat(
+        [
+          [1, 0, 1],
+          [1, 1, 0],
+          [1, 1, 0]
+        ]
+      )
+    )
+  end
+
+  def test_default_two
+    assert_equal(
+      24,
+      num_submat(
+        [
+          [0, 1, 1, 0],
+          [0, 1, 1, 1],
+          [1, 1, 1, 0]
+        ]
+      )
+    )
+  end
+end