2025-02-26 v. 8.7.2: added "1609. Even Odd Tree"

README.md

@@ -705,6 +705,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 1529. Minimum Suffix Flips                                                          | [Link](https://leetcode.com/problems/minimum-suffix-flips/)                                                          | [Link](./lib/medium/1529_minimum_suffix_flips.rb)                                                          | [Link](./test/medium/test_1529_minimum_suffix_flips.rb)                                                          |
 | 1530. Number of Good Leaf Nodes Pairs                                               | [Link](https://leetcode.com/problems/number-of-good-leaf-nodes-pairs/)                                               | [Link](./lib/medium/1530_number_of_good_leaf_nodes_pairs.rb)                                               | [Link](./test/medium/test_1530_number_of_good_leaf_nodes_pairs.rb)                                               |
 | 1557. Minimum Number of Vertices to Reach All Nodes                                 | [Link](https://leetcode.com/problems/minimum-number-of-vertices-to-reach-all-nodes/)                                 | [Link](./lib/medium/1557_minimum_number_of_vertices_to_reach_all_nodes.rb)                                 | [Link](./test/medium/test_1557_minimum_number_of_vertices_to_reach_all_nodes.rb)                                 |
+| 1609. Even Odd Tree                                                                 | [Link](https://leetcode.com/problems/even-odd-tree/)                                                                 | [Link](./lib/medium/1609_even_odd_tree.rb)                                                                 | [Link](./test/medium/test_1609_even_odd_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 = '8.7.1'
+  s.version = '8.7.2'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/medium/1609_even_odd_tree.rb

@@ -0,0 +1,34 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/even-odd-tree/
+# @param {TreeNode} root
+# @return {Boolean}
+def is_even_odd_tree(root)
+  nodes = [root]
+  level = 0
+
+  until nodes.empty?
+    size = nodes.size
+    prev = -1
+
+    (0...size).each do |_i|
+      node = nodes.shift
+      val = node.val
+
+      if level.even?
+        return false if val.even? || (prev != -1 && prev >= val)
+      elsif val.odd? || (prev != -1 && prev <= val)
+        return false
+      end
+
+      nodes << node.left if node.left
+      nodes << node.right if node.right
+
+      prev = val
+    end
+
+    level += 1
+  end
+
+  true
+end

test/medium/test_1609_even_odd_tree.rb

@@ -0,0 +1,38 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/common/binary_tree'
+require_relative '../../lib/medium/1609_even_odd_tree'
+require 'minitest/autorun'
+
+class EvenOddTreeTest < ::Minitest::Test
+  def test_default_one
+    assert(
+      is_even_odd_tree(
+        ::TreeNode.build_tree(
+          [1, 10, 4, 3, nil, 7, 9, 12, 8, 6, nil, nil, 2]
+        )
+      )
+    )
+  end
+
+  def test_default_two
+    assert(
+      !is_even_odd_tree(
+        ::TreeNode.build_tree(
+          [5, 4, 2, 3, 3, 7]
+        )
+      )
+    )
+  end
+
+  def test_default_three
+    assert(
+      !is_even_odd_tree(
+        ::TreeNode.build_tree(
+          [5, 9, 1, 3, 5, 7]
+        )
+      )
+    )
+  end
+end