From c0cd449edadc44c2036c8e45fafaf652e8a3ad08 Mon Sep 17 00:00:00 2001
From: fartem <jaman.smlnsk@gmail.com>
Date: Mon, 3 Feb 2025 21:02:22 +0300
Subject: [PATCH] 2025-02-03 v. 8.3.9: added "1261. Find Elements in a
 Contaminated Binary Tree"

---
 README.md                                     |  1 +
 leetcode-ruby.gemspec                         |  2 +-
 ..._elements_in_a_contaminated_binary_tree.rb | 39 ++++++++++++++++
 ..._elements_in_a_contaminated_binary_tree.rb | 44 +++++++++++++++++++
 4 files changed, 85 insertions(+), 1 deletion(-)
 create mode 100644 lib/medium/1261_find_elements_in_a_contaminated_binary_tree.rb
 create mode 100644 test/medium/test_1261_find_elements_in_a_contaminated_binary_tree.rb

diff --git a/README.md b/README.md
index ed466695..573eec50 100644
--- a/README.md
+++ b/README.md
@@ -671,6 +671,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 1247. Minimum Swaps to Make Strings Equal                        | [Link](https://leetcode.com/problems/minimum-swaps-to-make-strings-equal/)                         | [Link](./lib/medium/1247_minimum_swaps_to_make_strings_equal.rb)                        | [Link](./test/medium/test_1247_minimum_swaps_to_make_strings_equal.rb)                        |
 | 1248. Count Number of Nice Subarrays                             | [Link](https://leetcode.com/problems/count-number-of-nice-subarrays/)                              | [Link](./lib/medium/1248_count_number_of_nice_subarrays.rb)                             | [Link](./test/medium/test_1248_count_number_of_nice_subarrays.rb)                             |
 | 1249. Minimum Remove to Make Valid Parentheses                   | [Link](https://leetcode.com/problems/minimum-remove-to-make-valid-parentheses/)                    | [Link](./lib/medium/1249_minimum_remove_to_make_valid_parentheses.rb)                   | [Link](./test/medium/test_1249_minimum_remove_to_make_valid_parentheses.rb)                   |
+| 1261. Find Elements in a Contaminated Binary Tree                | [Link](https://leetcode.com/problems/find-elements-in-a-contaminated-binary-tree/)                 | [Link](./lib/medium/1261_find_elements_in_a_contaminated_binary_tree.rb)                | [Link](./test/medium/test_1261_find_elements_in_a_contaminated_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 d9cab579..6f79b56c 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 = '8.3.8'
+  s.version = '8.3.9'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'
diff --git a/lib/medium/1261_find_elements_in_a_contaminated_binary_tree.rb b/lib/medium/1261_find_elements_in_a_contaminated_binary_tree.rb
new file mode 100644
index 00000000..a41ccfd0
--- /dev/null
+++ b/lib/medium/1261_find_elements_in_a_contaminated_binary_tree.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/find-elements-in-a-contaminated-binary-tree/
+class FindElements
+  # @param {TreeNode} root
+  def initialize(root)
+    root.val = 0
+
+    @values = ::Set.new
+
+    recover(root)
+  end
+
+  # @param {Integer} target
+  # @return {Boolean}
+  def find(target) = @values.include?(target)
+
+  private
+
+  # @param {TreeNode} node
+  # @return {Void}
+  def recover(node)
+    return unless node
+
+    @values << node.val
+
+    if node.left
+      node.left.val = 2 * node.val + 1
+
+      recover(node.left)
+    end
+
+    return unless node.right
+
+    node.right.val = 2 * node.val + 2
+
+    recover(node.right)
+  end
+end
diff --git a/test/medium/test_1261_find_elements_in_a_contaminated_binary_tree.rb b/test/medium/test_1261_find_elements_in_a_contaminated_binary_tree.rb
new file mode 100644
index 00000000..80ecd666
--- /dev/null
+++ b/test/medium/test_1261_find_elements_in_a_contaminated_binary_tree.rb
@@ -0,0 +1,44 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/common/binary_tree'
+require_relative '../../lib/medium/1261_find_elements_in_a_contaminated_binary_tree'
+require 'minitest/autorun'
+
+class FindElementsInAContaminatedBinaryTreeTest < ::Minitest::Test
+  def test_case_one
+    find_elements = ::FindElements.new(
+      ::TreeNode.build_tree(
+        [-1, nil, -1]
+      )
+    )
+
+    assert(!find_elements.find(1))
+    assert(find_elements.find(2))
+  end
+
+  def test_case_two
+    find_elements = ::FindElements.new(
+      ::TreeNode.build_tree(
+        [-1, -1, -1, -1, -1]
+      )
+    )
+
+    assert(find_elements.find(1))
+    assert(find_elements.find(3))
+    assert(!find_elements.find(5))
+  end
+
+  def test_case_three
+    find_elements = ::FindElements.new(
+      ::TreeNode.build_tree(
+        [-1, nil, -1, -1, nil, -1]
+      )
+    )
+
+    assert(find_elements.find(2))
+    assert(!find_elements.find(3))
+    assert(!find_elements.find(4))
+    assert(find_elements.find(5))
+  end
+end