2025-02-13 v. 8.5.4: added "1382. Balance a Binary Search Tree"

Author: fartem

README.md

@@ -687,6 +687,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 1367. Linked List in Binary Tree                                                    | [Link](https://leetcode.com/problems/linked-list-in-binary-tree/)                                                    | [Link](./lib/medium/1367_linked_list_in_binary_tree.rb)                                                    | [Link](./test/medium/test_1367_linked_list_in_binary_tree.rb)                                                    |
 | 1376. Time Needed to Inform All Employees                                           | [Link](https://leetcode.com/problems/time-needed-to-inform-all-employees/)                                           | [Link](./lib/medium/1376_time_needed_to_inform_all_employees.rb)                                           | [Link](./test/medium/test_1376_time_needed_to_inform_all_employees.rb)                                           |
 | 1381. Design a Stack With Increment Operation                                       | [Link](https://leetcode.com/problems/design-a-stack-with-increment-operation/)                                       | [Link](./lib/medium/1381_design_a_stack_with_increment_operation.rb)                                       | [Link](./test/medium/test_1381_design_a_stack_with_increment_operation.rb)                                       |
+| 1382. Balance a Binary Search Tree                                                  | [Link](https://leetcode.com/problems/balance-a-binary-search-tree/)                                                  | [Link](./lib/medium/1382_balance_a_binary_search_tree.rb)                                                  | [Link](./test/medium/test_1382_balance_a_binary_search_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 = '8.5.4'
+  s.version = '8.5.5'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/medium/1382_balance_a_binary_search_tree.rb

@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+require_relative '../common/binary_tree'
+
+# https://leetcode.com/problems/balance-a-binary-search-tree/
+# @param {TreeNode} root
+# @return {TreeNode}
+def balance_bst(root)
+  nums = []
+  dfs_for_balance_bst(root, nums)
+
+  build_for_balance_bst(nums, 0, nums.size - 1)
+end
+
+private
+
+# @param {TreeNode} node
+# @param {Integer} nums
+# @return {Void}
+def dfs_for_balance_bst(node, nums)
+  return unless node
+
+  dfs_for_balance_bst(node.left, nums)
+  nums << node.val
+  dfs_for_balance_bst(node.right, nums)
+end
+
+# @param {Integer[]} nums
+# @param {Integer} left
+# @param {Integer} right
+# @return {TreeNode}
+def build_for_balance_bst(nums, left, right)
+  return if left > right
+
+  middle = left + (right - left) / 2
+  node = ::TreeNode.new(nums[middle])
+  node.left = build_for_balance_bst(nums, left, middle - 1)
+  node.right = build_for_balance_bst(nums, middle + 1, right)
+
+  node
+end

test/medium/test_1382_balance_a_binary_search_tree.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/common/binary_tree'
+require_relative '../../lib/medium/1382_balance_a_binary_search_tree'
+require 'minitest/autorun'
+
+class BalanceABinarySearchTreeTest < ::Minitest::Test
+  def test_default_one
+    assert(
+      ::TreeNode.are_equals(
+        ::TreeNode.build_tree(
+          [2, 1, 3, nil, nil, nil, 4]
+        ),
+        balance_bst(
+          ::TreeNode.build_tree(
+            [1, nil, 2, nil, 3, nil, 4, nil, nil]
+          )
+        )
+      )
+    )
+  end
+
+  def test_default_two
+    assert(
+      ::TreeNode.are_equals(
+        ::TreeNode.build_tree(
+          [2, 1, 3]
+        ),
+        balance_bst(
+          ::TreeNode.build_tree(
+            [2, 1, 3]
+          )
+        )
+      )
+    )
+  end
+end