2024-11-13 v. 7.0.2: added "424. Longest Repeating Character Replacement"

Author: fartem

README.md

@@ -567,3 +567,4 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 400. Nth Digit                                                  | [Link](https://leetcode.com/problems/nth-digit/)                                                  | [Link](./lib/medium/400_nth_digit.rb)                                                  | [Link](./test/medium/test_400_nth_digit.rb)                                                  |
 | 402. Remove K Digits                                            | [Link](https://leetcode.com/problems/remove-k-digits/)                                            | [Link](./lib/medium/402_remove_k_digits.rb)                                            | [Link](./test/medium/test_402_remove_k_digits.rb)                                            |
 | 417. Pacific Atlantic Water Flow                                | [Link](https://leetcode.com/problems/pacific-atlantic-water-flow/)                                | [Link](./lib/medium/417_pacific_atlantic_water_flow.rb)                                | [Link](./test/medium/test_417_pacific_atlantic_water_flow.rb)                                |
+| 424. Longest Repeating Character Replacement                    | [Link](https://leetcode.com/problems/longest-repeating-character-replacement/)                    | [Link](./lib/medium/424_longest_repeating_character_replacement.rb)                    | [Link](./test/medium/test_424_longest_repeating_character_replacement.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 = '7.0.1'
+  s.version = '7.0.2'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/medium/424_longest_repeating_character_replacement.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/longest-repeating-character-replacement/
+# @param {String} s
+# @param {Integer} k
+# @return {Integer}
+def character_replacement(s, k)
+  freq = ::Array.new(128, 0)
+  f = 0
+  e = 0
+  max = 0
+  result = 0
+
+  while e < s.size
+    i = s[e].ord
+    freq[i] += 1
+    max = [max, freq[i]].max
+
+    curr = e - f + 1
+    if curr - max > k
+      freq[s[f].ord] -= 1
+      f += 1
+    end
+
+    result = [result, e - f + 1].max
+
+    e += 1
+  end
+
+  result
+end

test/medium/test_424_longest_repeating_character_replacement.rb

@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/424_longest_repeating_character_replacement'
+require 'minitest/autorun'
+
+class LongestRepeatingCharacterReplacementTest < ::Minitest::Test
+  def test_default_one = assert_equal(4, character_replacement('ABAB', 2))
+
+  def test_default_two = assert_equal(4, character_replacement('AABABBA', 1))
+end