2025-02-18 v. 8.6.1: added "1448. Count Good Nodes in Binary Tree"

README.md

@@ -694,6 +694,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 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)                                                |
 | 1433. Check If a String Can Break Another String                                    | [Link](https://leetcode.com/problems/check-if-a-string-can-break-another-string/)                                    | [Link](./lib/medium/1433_check_if_a_string_can_break_another_string.rb)                                    | [Link](./test/medium/test_1433_check_if_a_string_can_break_another_string.rb)                                    |
 | 1442. Count Triplets That Can Form Two Arrays of Equal XOR                          | [Link](https://leetcode.com/problems/count-triplets-that-can-form-two-arrays-of-equal-xor/)                          | [Link](./lib/medium/1442_count_triplets_that_can_form_two_arrays_of_equal_xor.rb)                          | [Link](./test/medium/test_1442_count_triplets_that_can_form_two_arrays_of_equal_xor.rb)                          |
+| 1448. Count Good Nodes in Binary Tree                                               | [Link](https://leetcode.com/problems/count-good-nodes-in-binary-tree/)                                               | [Link](./lib/medium/1448_count_good_nodes_in_binary_tree.rb)                                               | [Link](./test/medium/test_1448_count_good_nodes_in_binary_tree.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)                                                                  |

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 = '8.6.0'
+  s.version = '8.6.1'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/medium/1448_count_good_nodes_in_binary_tree.rb

@@ -0,0 +1,20 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/count-good-nodes-in-binary-tree/
+# @param {TreeNode} root
+# @return {Integer}
+def good_nodes(root) = dfs_for_good_nodes(root, root.val)
+
+private
+
+# @param {TreeNode} node
+# @param {Integer} curr_max
+# @return {Integer}
+def dfs_for_good_nodes(node, curr_max)
+  return 0 unless node
+
+  left = dfs_for_good_nodes(node.left, [curr_max, node.val].max)
+  right = dfs_for_good_nodes(node.right, [curr_max, node.val].max)
+
+  (node.val >= curr_max ? 1 : 0) + left + right
+end

test/medium/test_1448_count_good_nodes_in_binary_tree.rb

@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/common/binary_tree'
+require_relative '../../lib/medium/1448_count_good_nodes_in_binary_tree'
+require 'minitest/autorun'
+
+class CountGoodNodesInBinaryTreeTest < ::Minitest::Test
+  def test_default_one
+    assert_equal(
+      4,
+      good_nodes(
+        ::TreeNode.build_tree(
+          [3, 1, 4, 3, nil, 1, 5]
+        )
+      )
+    )
+  end
+
+  def test_default_two
+    assert_equal(
+      3,
+      good_nodes(
+        ::TreeNode.build_tree(
+          [3, 3, nil, 4, 2]
+        )
+      )
+    )
+  end
+
+  def test_default_three
+    assert_equal(
+      1,
+      good_nodes(
+        ::TreeNode.build_tree(
+          [1]
+        )
+      )
+    )
+  end
+end