2025-01-31 v. 8.3.7: added "1248. Count Number of Nice Subarrays"

Author: fartem

README.md

@@ -669,6 +669,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 1171. Remove Zero Sum Consecutive Nodes from Linked List         | [Link](https://leetcode.com/problems/remove-zero-sum-consecutive-nodes-from-linked-list/)          | [Link](./lib/medium/1171_remove_zero_sum_consecutive_nodes_from_linked_list.rb)         | [Link](./test/medium/test_1171_remove_zero_sum_consecutive_nodes_from_linked_list.rb)         |
 | 1209. Remove All Adjacent Duplicates in String II                | [Link](https://leetcode.com/problems/remove-all-adjacent-duplicates-in-string-ii/)                 | [Link](./lib/medium/1209_remove_all_adjacent_duplicates_in_string_ii.rb)                | [Link](./test/medium/test_1209_remove_all_adjacent_duplicates_in_string_ii.rb)                |
 | 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)                             |
 | 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 = '8.3.6'
+  s.version = '8.3.7'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/medium/1248_count_number_of_nice_subarrays.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/count-number-of-nice-subarrays/
+# @param {Integer[]} nums
+# @param {Integer} k
+# @return {Integer}
+def number_of_subarrays(nums, k)
+  prefix = ::Array.new(nums.size + 1, 0)
+  max = 0
+  count = 0
+
+  nums.each do |num|
+    prefix[count] += 1
+
+    count += 1 if num.odd?
+
+    max += prefix[count - k] if count >= k
+  end
+
+  max
+end

test/medium/test_1248_count_number_of_nice_subarrays.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/1248_count_number_of_nice_subarrays'
+require 'minitest/autorun'
+
+class CountNumberOfNiceSubarraysTest < ::Minitest::Test
+  def test_default_one
+    assert_equal(
+      2,
+      number_of_subarrays(
+        [1, 1, 2, 1, 1],
+        3
+      )
+    )
+  end
+
+  def test_default_two
+    assert_equal(
+      0,
+      number_of_subarrays(
+        [2, 4, 6],
+        1
+      )
+    )
+  end
+
+  def test_default_three
+    assert_equal(
+      16,
+      number_of_subarrays(
+        [2, 2, 2, 1, 2, 2, 1, 2, 2, 2],
+        2
+      )
+    )
+  end
+end