2025-01-13 v. 7.9.6: added "921. Minimum Add to Make Parentheses Valid"

Author: fartem

README.md

@@ -641,6 +641,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 912. Sort an Array                                               | [Link](https://leetcode.com/problems/sort-an-array/)                                               | [Link](./lib/medium/912_sort_an_array.rb)                                               | [Link](./test/medium/test_912_sort_an_array.rb)                                               |
 | 916. Word Subsets                                                | [Link](https://leetcode.com/problems/word-subsets/)                                                | [Link](./lib/medium/916_word_subsets.rb)                                                | [Link](./test/medium/test_916_word_subsets.rb)                                                |
 | 919. Complete Binary Tree Inserter                               | [Link](https://leetcode.com/problems/complete-binary-tree-inserter/)                               | [Link](./lib/medium/919_complete_binary_tree_inserter.rb)                               | [Link](./test/medium/test_919_complete_binary_tree_inserter.rb)                               |
+| 921. Minimum Add to Make Parentheses Valid                       | [Link](https://leetcode.com/problems/minimum-add-to-make-parentheses-valid/)                       | [Link](./lib/medium/921_minimum_add_to_make_parentheses_valid.rb)                       | [Link](./test/medium/test_921_minimum_add_to_make_parentheses_valid.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)                 |
 | 3223. Minimum Length of String After Operations                  | [Link](https://leetcode.com/problems/minimum-length-of-string-after-operations/)                   | [Link](./lib/medium/3223_minimum_length_of_string_after_operations.rb)                  | [Link](./test/medium/test_3223_minimum_length_of_string_after_operations.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 = '7.9.5'
+  s.version = '7.9.6'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/medium/921_minimum_add_to_make_parentheses_valid.rb

@@ -0,0 +1,23 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/minimum-add-to-make-parentheses-valid/
+# @param {String} s
+# @return {Integer}
+def min_add_to_make_valid(s)
+  o = 0
+  c = 0
+
+  s.each_char do |char|
+    if char == ')'
+      if o.zero?
+        c += 1
+      else
+        o -= 1
+      end
+    else
+      o += 1
+    end
+  end
+
+  o + c
+end

test/medium/test_921_minimum_add_to_make_parentheses_valid.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/921_minimum_add_to_make_parentheses_valid'
+require 'minitest/autorun'
+
+class MinimumAddToMakeParenthesesValidTest < ::Minitest::Test
+  def test_default_one = assert_equal(1, min_add_to_make_valid('())'))
+
+  def test_default_two = assert_equal(3, min_add_to_make_valid('((('))
+end