Merge pull request #694 from fartem/99_Recover_Binary_Search_Tree

2024-08-30 v. 6.3.5: added "99. Recover Binary Search Tree"

Author: fartem

README.md

@@ -13,7 +13,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 ### Easy
 
 | Name                                                               | Link to LeetCode                                                                                    | Link to solution                                                                        |
-|--------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------|
+| ------------------------------------------------------------------ | --------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------- |
 | 1. Two Sum                                                         | [Link](https://leetcode.com/problems/two-sum/)                                                      | [Link](./lib/easy/1_two_sum.rb)                                                         |
 | 9. Palindrome Number                                               | [Link](https://leetcode.com/problems/palindrome-number/)                                            | [Link](./lib/easy/9_palindrome_number.rb)                                               |
 | 13. Roman to Integer                                               | [Link](https://leetcode.com/problems/roman-to-integer/)                                             | [Link](./lib/easy/13_roman_to_integer.rb)                                               |
@@ -458,7 +458,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 ### Medium
 
 | Name                                                        | Link to LeetCode                                                                               | Link to solution                                                                   |
-|-------------------------------------------------------------|------------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------|
+| ----------------------------------------------------------- | ---------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------- |
 | 2. Add Two Numbers                                          | [Link](https://leetcode.com/problems/add-two-numbers/)                                         | [Link](./lib/medium/2_add_two_numbers.rb)                                          |
 | 3. Longest Substring Without Repeating Characters           | [Link](https://leetcode.com/problems/longest-substring-without-repeating-characters/)          | [Link](./lib/medium/3_longest_substring_without_repeating_characters.rb)           |
 | 5. Longest Palindromic Substring                            | [Link](https://leetcode.com/problems/longest-palindromic-substring/)                           | [Link](./lib/medium/5_longest_palindromic_substring.rb)                            |
@@ -500,3 +500,4 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 95. Unique Binary Search Trees II                           | [Link](https://leetcode.com/problems/unique-binary-search-trees-ii/)                           | [Link](./lib/medium/95_unique_binary_search_trees_ii.rb)                           |
 | 96. Unique Binary Search Trees                              | [Link](https://leetcode.com/problems/unique-binary-search-trees/)                              | [Link](./lib/medium/96_unique_binary_search_trees.rb)                              |
 | 98. Validate Binary Search Tree                             | [Link](https://leetcode.com/problems/validate-binary-search-tree/)                             | [Link](./lib/medium/98_validate_binary_search_tree.rb)                             |
+| 99. Recover Binary Search Tree                              | [Link](https://leetcode.com/problems/recover-binary-search-tree/)                              | [Link](./lib/medium/99_recover_binary_search_tree.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 = '6.3.4'
+  s.version = '6.3.5'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/medium/99_recover_binary_search_tree.rb

@@ -0,0 +1,45 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/recover-binary-search-tree/
+# @param {TreeNode} root
+# @return {Void} Do not return anything, modify root in-place instead.
+def recover_tree(root)
+  nodes = []
+  traverse99(root, nodes)
+  first = nil
+  (0...(nodes.length - 1)).each do |i|
+    curr = nodes[i]
+    nxt = nodes[i + 1]
+
+    puts(curr.val)
+    puts(nxt.val)
+
+    first = nxt if nxt.val < curr.val
+  end
+
+  second = nodes.first
+  (1...nodes.length).each do |i|
+    prev = nodes[i - 1]
+    curr = nodes[i]
+
+    next unless prev.val < first.val && first.val < curr.val
+
+    second = curr
+
+    break
+  end
+
+  temp = first.val
+  first.val = second.val
+  second.val = temp
+end
+
+private
+
+def traverse99(root, nodes)
+  return unless root
+
+  traverse99(root.left, nodes)
+  nodes << root
+  traverse99(root.right, nodes)
+end

test/medium/test_99_recover_binary_search_tree.rb

@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/common/binary_tree'
+require_relative '../../lib/medium/99_recover_binary_search_tree'
+require 'minitest/autorun'
+
+class RecoverBinarySearchTreeTest < ::Minitest::Test
+  def test_default
+    input = ::TreeNode.new(
+      1,
+      ::TreeNode.new(
+        3,
+        nil,
+        ::TreeNode.new(2)
+      ),
+      nil
+    )
+    recover_tree(input)
+
+    assert(
+      ::TreeNode.are_equals(
+        ::TreeNode.new(
+          3,
+          ::TreeNode.new(
+            1,
+            nil,
+            ::TreeNode.new(2)
+          ),
+          nil
+        ),
+        input
+      )
+    )
+
+    input = ::TreeNode.new(
+      3,
+      ::TreeNode.new(1),
+      ::TreeNode.new(
+        4,
+        ::TreeNode.new(2),
+        nil
+      )
+    )
+    recover_tree(input)
+
+    assert(
+      ::TreeNode.are_equals(
+        ::TreeNode.new(
+          2,
+          ::TreeNode.new(1),
+          ::TreeNode.new(
+            4,
+            ::TreeNode.new(3),
+            nil
+          )
+        ),
+        input
+      )
+    )
+  end
+end