Merge pull request #758 from fartem/347_Top_K_Frequent_Elements

2024-10-28 v. 6.9.0: added "347. Top K Frequent Elements"

Author: fartem

README.md

@@ -555,3 +555,4 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 331. Verify Preorder Serialization of a Binary Tree             | [Link](https://leetcode.com/problems/verify-preorder-serialization-of-a-binary-tree/)             | [Link](./lib/medium/331_verify_preorder_serialization_of_a_binary_tree.rb)             | [Link](./test/medium/test_331_verify_preorder_serialization_of_a_binary_tree.rb)             |
 | 334. Increasing Triplet Subsequence                             | [Link](https://leetcode.com/problems/increasing-triplet-subsequence/)                             | [Link](./lib/medium/334_increasing_triplet_subsequence.rb)                             | [Link](./test/medium/test_334_increasing_triplet_subsequence.rb)                             |
 | 341. Flatten Nested List Iterator                               | [Link](https://leetcode.com/problems/flatten-nested-list-iterator/)                               | [Link](./lib/medium/341_flatten_nested_list_iterator.rb)                               | [Link](./test/medium/test_341_flatten_nested_list_iterator.rb)                               |
+| 347. Top K Frequent Elements                                    | [Link](https://leetcode.com/problems/top-k-frequent-elements/)                                    | [Link](./lib/medium/347_top_k_frequent_elements.rb)                                    | [Link](./test/medium/test_347_top_k_frequent_elements.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 = '6.8.9.1'
+  s.version = '6.9.0'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/medium/347_top_k_frequent_elements.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/top-k-frequent-elements/description/
+# @param {Integer[]} nums
+# @param {Integer} k
+# @return {Integer[]}
+def top_k_frequent(nums, k)
+  values = ::Hash.new(0)
+  nums.each { |num| values[num] += 1 }
+  queue = values.sort_by { |_, v| -v }.first(k)
+
+  queue.map { |num, _| num }
+end

test/medium/test_341_flatten_nested_list_iterator.rb

@@ -34,8 +34,6 @@ def test_default_one
   end
 
   def test_default_two
-    # [1,[4,[6]]]
-
     nested_iterator = ::NestedIterator.new(
       [
         ::NestedInteger.new(1),

test/medium/test_347_top_k_frequent_elements.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/347_top_k_frequent_elements'
+require 'minitest/autorun'
+
+class TopKFrequentElementsTest < ::Minitest::Test
+  def test_default_one
+    assert_equal(
+      [1, 2],
+      top_k_frequent(
+        [1, 1, 1, 2, 2, 3],
+        2
+      )
+    )
+  end
+
+  def test_default_two
+    assert_equal(
+      [1],
+      top_k_frequent(
+        [1],
+        1
+      )
+    )
+  end
+end