2025-01-02 v. 7.6.2: updated "823. Binary Trees With Factors"

Author: fartem

README.md

@@ -624,6 +624,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 797. All Paths From Source to Target                            | [Link](https://leetcode.com/problems/all-paths-from-source-to-target/)                            | [Link](./lib/medium/797_all_paths_from_source_to_target.rb)                            | [Link](./test/medium/test_797_all_paths_from_source_to_target.rb)                            |
 | 814. Binary Tree Pruning                                        | [Link](https://leetcode.com/problems/binary-tree-pruning/)                                        | [Link](./lib/medium/814_binary_tree_pruning.rb)                                        | [Link](./test/medium/test_814_binary_tree_pruning.rb)                                        |
 | 817. Linked List Components                                     | [Link](https://leetcode.com/problems/linked-list-components/)                                     | [Link](./lib/medium/817_linked_list_components.rb)                                     | [Link](./test/medium/test_817_linked_list_components.rb)                                     |
+| 823. Binary Trees With Factors                                  | [Link](https://leetcode.com/problems/binary-trees-with-factors/)                                  | [Link](./lib/medium/823_binary_trees_with_factors.rb)                                  | [Link](./test/medium/test_823_binary_trees_with_factors.rb)                                  |
 
 ### Hard
 

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 = '7.6.1'
+  s.version = '7.6.2'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/medium/823_binary_trees_with_factors.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/binary-trees-with-factors/
+# @param {Integer[]} arr
+# @return {Integer}
+def num_factored_binary_trees(arr)
+  mod = 1_000_000_007
+  arr.sort!
+  dp = ::Array.new(arr.size, 1)
+  index = {}
+  arr.each_with_index { |val, i| index[val] = i }
+  (0...arr.size).each do |i|
+    (0...i).each do |j|
+      next unless (arr[i] % arr[j]).zero?
+
+      r = arr[i] / arr[j]
+
+      dp[i] = (dp[i] + dp[j] * dp[index[r]]) % mod if index.key?(r)
+    end
+  end
+
+  result = 0
+  dp.each { |val| result = (result + val) % mod }
+
+  result
+end

test/medium/test_823_binary_trees_with_factors.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/823_binary_trees_with_factors'
+require 'minitest/autorun'
+
+class BinaryTreesWithFactorsTest < ::Minitest::Test
+  def test_default_one
+    assert_equal(
+      3,
+      num_factored_binary_trees(
+        [2, 4]
+      )
+    )
+  end
+
+  def test_default_two
+    assert_equal(
+      7,
+      num_factored_binary_trees(
+        [2, 4, 5, 10]
+      )
+    )
+  end
+end