2025-01-14 v. 7.9.9: added "2657. Find the Prefix Common Array of Two Arrays"

Author: fartem

README.md

@@ -644,6 +644,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 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)                 |
+| 2657. Find the Prefix Common Array of Two Arrays                 | [Link](https://leetcode.com/problems/find-the-prefix-common-array-of-two-arrays/)                  | [Link](./lib/medium/2657_find_the_prefix_common_array_of_two_arrays.rb)                 | [Link](./test/medium/test_2657_find_the_prefix_common_array_of_two_arrays.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)                  |
 
 ### 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 = '7.9.8'
+  s.version = '7.9.9'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/medium/2657_find_the_prefix_common_array_of_two_arrays.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/find-the-prefix-common-array-of-two-arrays/
+# @param {Integer[]} a
+# @param {Integer[]} b
+# @return {Integer[]}
+def find_the_prefix_common_array(a, b)
+  n = a.size
+  freq = ::Array.new(n + 1, 0)
+  result = ::Array.new(n, 0)
+  common = 0
+
+  (0...n).each do |i|
+    freq[a[i]] += 1
+    common += 1 if freq[a[i]] == 2
+
+    freq[b[i]] += 1
+    common += 1 if freq[b[i]] == 2
+
+    result[i] = common
+  end
+
+  result
+end

test/medium/test_2657_find_the_prefix_common_array_of_two_arrays.rb

@@ -0,0 +1,27 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/2657_find_the_prefix_common_array_of_two_arrays'
+require 'minitest/autorun'
+
+class FindThePrefixCommonArrayOfTwoArraysTest < ::Minitest::Test
+  def test_default_one
+    assert_equal(
+      [0, 2, 3, 4],
+      find_the_prefix_common_array(
+        [1, 3, 2, 4],
+        [3, 1, 2, 4]
+      )
+    )
+  end
+
+  def test_default_two
+    assert_equal(
+      [0, 1, 3],
+      find_the_prefix_common_array(
+        [2, 3, 1],
+        [3, 1, 2]
+      )
+    )
+  end
+end