diff --git a/README.md b/README.md
index bd8174dd..06780eca 100644
--- a/README.md
+++ b/README.md
@@ -680,6 +680,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 1325. Delete Leaves With a Given Value                           | [Link](https://leetcode.com/problems/delete-leaves-with-a-given-value/)                            | [Link](./lib/medium/1325_delete_leaves_with_a_given_value.rb)                           | [Link](./test/medium/test_1325_delete_leaves_with_a_given_value.rb)                           |
 | 1329. Sort the Matrix Diagonally                                 | [Link](https://leetcode.com/problems/sort-the-matrix-diagonally/)                                  | [Link](./lib/medium/1329_sort_the_matrix_diagonally.rb)                                 | [Link](./test/medium/test_1329_sort_the_matrix_diagonally.rb)                                 |
 | 1338. Reduce Array Size to The Half                              | [Link](https://leetcode.com/problems/reduce-array-size-to-the-half/)                               | [Link](./lib/medium/1338_reduce_array_size_to_the_half.rb)                              | [Link](./test/medium/test_1338_reduce_array_size_to_the_half.rb)                              |
+| 1339. Maximum Product of Splitted Binary Tree                    | [Link](https://leetcode.com/problems/maximum-product-of-splitted-binary-tree/)                     | [Link](./lib/medium/1339_maximum_product_of_splitted_binary_tree.rb)                    | [Link](./test/medium/test_1339_maximum_product_of_splitted_binary_tree.rb)                    |
 | 1400. Construct K Palindrome Strings                             | [Link](https://leetcode.com/problems/construct-k-palindrome-strings/)                              | [Link](./lib/medium/1400_construct_k_palindrome_strings.rb)                             | [Link](./test/medium/test_1400_construct_k_palindrome_strings.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)                                |
diff --git a/leetcode-ruby.gemspec b/leetcode-ruby.gemspec
index 4cbf4fdd..31f77bde 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 = '8.4.7'
+  s.version = '8.4.8'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'
diff --git a/lib/medium/1339_maximum_product_of_splitted_binary_tree.rb b/lib/medium/1339_maximum_product_of_splitted_binary_tree.rb
new file mode 100644
index 00000000..2e3c8544
--- /dev/null
+++ b/lib/medium/1339_maximum_product_of_splitted_binary_tree.rb
@@ -0,0 +1,36 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/maximum-product-of-splitted-binary-tree/
+# @param {TreeNode} root
+# @return {Integer}
+def max_product_for_splitted_binary_tree(root)
+  @sum = sum_for_splitted_binary_tree(root)
+  @result = 0
+
+  calculate_for_splitted_binary_tree(root)
+
+  (@result % (1e9 + 7)).to_i
+end
+
+private
+
+# @param {TreeNode}
+# @return {Integer}
+def sum_for_splitted_binary_tree(node)
+  return 0 unless node
+
+  sum_for_splitted_binary_tree(node.left) + sum_for_splitted_binary_tree(node.right) + node.val
+end
+
+# @param {TreeNode}
+# @return {Integer}
+def calculate_for_splitted_binary_tree(node)
+  return 0 unless node
+
+  f_sum = calculate_for_splitted_binary_tree(node.left) + calculate_for_splitted_binary_tree(node.right) + node.val
+  s_sum = @sum - f_sum
+
+  @result = [@result, f_sum * s_sum].max
+
+  f_sum
+end
diff --git a/test/medium/test_1339_maximum_product_of_splitted_binary_tree.rb b/test/medium/test_1339_maximum_product_of_splitted_binary_tree.rb
new file mode 100644
index 00000000..d5153752
--- /dev/null
+++ b/test/medium/test_1339_maximum_product_of_splitted_binary_tree.rb
@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/common/binary_tree'
+require_relative '../../lib/medium/1339_maximum_product_of_splitted_binary_tree'
+require 'minitest/autorun'
+
+class MaximumProductOfSplittedBinaryTreeTest < ::Minitest::Test
+  def test_default_one
+    assert_equal(
+      110,
+      max_product_for_splitted_binary_tree(
+        ::TreeNode.build_tree(
+          [1, 2, 3, 4, 5, 6]
+        )
+      )
+    )
+  end
+
+  def test_default_two
+    assert_equal(
+      90,
+      max_product_for_splitted_binary_tree(
+        ::TreeNode.build_tree(
+          [1, nil, 2, 3, 4, nil, nil, 5, 6]
+        )
+      )
+    )
+  end
+end