Merge pull request #670 from fartem/43_Multiply_Strings

2024-07-12 v. 6.1.3: added "43. Multiply Strings"

Author: fartem

README.md

@@ -478,3 +478,4 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 36. Valid Sudoku                                            | [Link](https://leetcode.com/problems/valid-sudoku/)                                            | [Link](./lib/medium/36_valid_sudoku.rb)                                            |
 | 38. Count and Say                                           | [Link](https://leetcode.com/problems/count-and-say/)                                           | [Link](./lib/medium/38_count_and_say.rb)                                           |
 | 39. Combination Sum                                         | [Link](https://leetcode.com/problems/combination-sum/)                                         | [Link](./lib/medium/39_combination_sum.rb)                                         |
+| 43. Multiply Strings                                        | [Link](https://leetcode.com/problems/multiply-strings/)                                        | [Link](./lib/medium/43_multiply_strings.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 = '6.1.2'
+  s.version = '6.1.3'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[bin/leetcode-ruby README.md LICENSE]
   s.executable = 'leetcode-ruby'

lib/medium/43_multiply_strings.rb

@@ -0,0 +1,30 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/multiply-strings/
+# @param {String} num1
+# @param {String} num2
+# @return {String}
+def multiply(num1, num2)
+  a = convert_to_int(num1)
+  b = convert_to_int(num2)
+  c = a * b
+
+  c.to_s
+end
+
+private
+
+# @param {String} num
+# @return {Integer}
+def convert_to_int(num)
+  decimal_place = 1
+  reverse_num = num.reverse
+  int_value = 0
+
+  num.size.times do |i|
+    int_value += (reverse_num[i].ord - '0'.ord) * decimal_place
+    decimal_place *= 10
+  end
+
+  int_value
+end

test/medium/test_43_multiply_strings.rb

@@ -0,0 +1,12 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/43_multiply_strings'
+require 'minitest/autorun'
+
+class MultiplyStringsTest < ::Minitest::Test
+  def test_default
+    assert_equal('6', multiply('2', '3'))
+    assert_equal('56088', multiply('123', '456'))
+  end
+end