2025-01-29 v. 8.3.2: added "1123. Lowest Common Ancestor of Deepest Leaves"

Author: fartem

README.md

@@ -664,6 +664,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 1081. Smallest Subsequence of Distinct Characters                | [Link](https://leetcode.com/problems/smallest-subsequence-of-distinct-characters/)                 | [Link](./lib/medium/1081_smallest_subsequence_of_distinct_characters.rb)                | [Link](./test/medium/test_1081_smallest_subsequence_of_distinct_characters.rb)                |
 | 1110. Delete Nodes And Return Forest                             | [Link](https://leetcode.com/problems/delete-nodes-and-return-forest/)                              | [Link](./lib/medium/1110_delete_nodes_and_return_forest.rb)                             | [Link](./test/medium/test_1110_delete_nodes_and_return_forest.rb)                             |
 | 1111. Maximum Nesting Depth of Two Valid Parentheses Strings     | [Link](https://leetcode.com/problems/maximum-nesting-depth-of-two-valid-parentheses-strings/)      | [Link](./lib/medium/1111_maximum_nesting_depth_of_two_valid_parentheses_strings.rb)     | [Link](./test/medium/test_1111_maximum_nesting_depth_of_two_valid_parentheses_strings.rb)     |
+| 1123. Lowest Common Ancestor of Deepest Leaves                   | [Link](https://leetcode.com/problems/lowest-common-ancestor-of-deepest-leaves/)                    | [Link](./lib/medium/1123_lowest_common_ancestor_of_deepest_leaves.rb)                   | [Link](./test/medium/test_1123_lowest_common_ancestor_of_deepest_leaves.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 = '8.3.1'
+  s.version = '8.3.2'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/medium/1123_lowest_common_ancestor_of_deepest_leaves.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/lowest-common-ancestor-of-deepest-leaves/
+# @param {TreeNode} root
+# @return {TreeNode}
+def lca_deepest_leaves(root)
+  return unless root
+
+  find_deepest_and_lca(root, 0)[1]
+end
+
+private
+
+# @param {TreeNode} node
+# @param {Integer} depth
+# @return {TreeNode}
+def find_deepest_and_lca(node, depth)
+  return [depth, node] unless node
+
+  left_depth, left_lca = find_deepest_and_lca(node.left, depth + 1)
+  right_depth, right_lca = find_deepest_and_lca(node.right, depth + 1)
+
+  if left_depth == right_depth
+    [left_depth, node]
+  elsif left_depth > right_depth
+    [left_depth, left_lca]
+  else
+    [right_depth, right_lca]
+  end
+end

test/medium/test_1123_lowest_common_ancestor_of_deepest_leaves.rb

@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/common/binary_tree'
+require_relative '../../lib/medium/1123_lowest_common_ancestor_of_deepest_leaves'
+require 'minitest/autorun'
+
+class LowestCommonAncestorOfDeepestLeavesTest < ::Minitest::Test
+  def test_default_one
+    assert(
+      ::TreeNode.are_equals(
+        lca_deepest_leaves(
+          ::TreeNode.build_tree(
+            [3, 5, 1, 6, 2, 0, 8, nil, nil, 7, 4]
+          )
+        ),
+        ::TreeNode.build_tree(
+          [2, 7, 4]
+        )
+      )
+    )
+  end
+
+  def test_default_two
+    assert(
+      ::TreeNode.are_equals(
+        lca_deepest_leaves(
+          ::TreeNode.build_tree(
+            [1]
+          )
+        ),
+        ::TreeNode.build_tree(
+          [1]
+        )
+      )
+    )
+  end
+
+  def test_default_three
+    assert(
+      ::TreeNode.are_equals(
+        lca_deepest_leaves(
+          ::TreeNode.build_tree(
+            [0, 1, 3, nil, 2]
+          )
+        ),
+        ::TreeNode.build_tree(
+          [2]
+        )
+      )
+    )
+  end
+end