2025-01-24 v. 8.2.6: added "1038. Binary Search Tree to Greater Sum Tree"

Author: fartem

README.md

@@ -658,6 +658,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 1019. Next Greater Node In Linked List                           | [Link](https://leetcode.com/problems/next-greater-node-in-linked-list/)                            | [Link](./lib/medium/1019_next_greater_node_in_linked_list.rb)                           | [Link](./test/medium/test_1019_next_greater_node_in_linked_list.rb)                           |
 | 1023. Camelcase Matching                                         | [Link](https://leetcode.com/problems/camelcase-matching/)                                          | [Link](./lib/medium/1023_camelcase_matching.rb)                                         | [Link](./test/medium/test_1023_camelcase_matching.rb)                                         |
 | 1026. Maximum Difference Between Node and Ancestor               | [Link](https://leetcode.com/problems/maximum-difference-between-node-and-ancestor/)                | [Link](./lib/medium/1026_maximum_difference_between_node_and_ancestor.rb)               | [Link](./test/medium/test_1026_maximum_difference_between_node_and_ancestor.rb)               |
+| 1038. Binary Search Tree to Greater Sum Tree                     | [Link](https://leetcode.com/problems/binary-search-tree-to-greater-sum-tree/)                      | [Link](./lib/medium/1038_binary_search_tree_to_greater_sum_tree.rb)                     | [Link](./test/medium/test_1038_binary_search_tree_to_greater_sum_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)                                |

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 = '8.2.5.9'
+  s.version = '8.2.6'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/medium/1038_binary_search_tree_to_greater_sum_tree.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/binary-search-tree-to-greater-sum-tree/
+# @param {Integer[]} arr
+# @param {Integer} k
+# @return {Integer}
+def max_sum_after_partitioning(arr, k)
+  partitioned = ::Array.new(arr.size + 1, 0)
+
+  (1..arr.size).each do |i|
+    max = 0
+    val = 0
+
+    [i, k].min.times do |j|
+      max = [max, arr[i - j - 1]].max
+      val = [partitioned[i - j - 1] + max * (j + 1), val].max
+    end
+
+    partitioned[i] = val
+  end
+
+  partitioned[arr.size]
+end

test/medium/test_1038_binary_search_tree_to_greater_sum_tree.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/1038_binary_search_tree_to_greater_sum_tree'
+require 'minitest/autorun'
+
+class BinarySearchTreeToGreaterSumTreeTest < ::Minitest::Test
+  def test_default_one
+    assert_equal(
+      84,
+      max_sum_after_partitioning(
+        [1, 15, 7, 9, 2, 5, 10],
+        3
+      )
+    )
+  end
+
+  def test_default_two
+    assert_equal(
+      83,
+      max_sum_after_partitioning(
+        [1, 4, 1, 5, 7, 3, 6, 1, 9, 9, 3],
+        4
+      )
+    )
+  end
+
+  def test_default_three
+    assert_equal(
+      1,
+      max_sum_after_partitioning(
+        [1],
+        1
+      )
+    )
+  end
+end