Merge pull request #637 from fartem/2485_Find_the_Pivot_Integer

2024-06-03 v. 5.8.0: added "2485. Find the Pivot Integer"

Author: fartem

README.md

@@ -440,3 +440,4 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 2469. Convert the Temperature                                      | [Link](https://leetcode.com/problems/convert-the-temperature/)                                      | [Link](./lib/easy/2469_convert_the_temperature.rb)                                      |
 | 2475. Number of Unequal Triplets in Array                          | [Link](https://leetcode.com/problems/number-of-unequal-triplets-in-array/)                          | [Link](./lib/easy/2475_number_of_unequal_triplets_in_array.rb)                          |
 | 2481. Minimum Cuts to Divide a Circle                              | [Link](https://leetcode.com/problems/minimum-cuts-to-divide-a-circle/)                              | [Link](./lib/easy/2481_minimum_cuts_to_divide_a_circle.rb)                              |
+| 2485. Find the Pivot Integer                                       | [Link](https://leetcode.com/problems/find-the-pivot-integer/)                                       | [Link](./lib/easy/2485_find_the_pivot_integer.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 = '5.7.9'
+  s.version = '5.8.0'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[bin/leetcode-ruby README.md LICENSE]
   s.executable = 'leetcode-ruby'

lib/easy/2485_find_the_pivot_integer.rb

@@ -0,0 +1,18 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/find-the-pivot-integer/
+# @param {Integer} n
+# @return {Integer}
+def pivot_integer(n)
+  sum = n * (n + 1) / 2
+  value = 0
+  (0..n).reverse_each do |i|
+    value += i
+
+    return i if sum == value
+
+    sum -= i
+  end
+
+  -1
+end

test/easy/test_2485_find_the_pivot_integer.rb

@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/easy/2485_find_the_pivot_integer'
+require 'minitest/autorun'
+
+class FindThePivotIntegerTest < ::Minitest::Test
+  def test_default
+    assert_equal(6, pivot_integer(8))
+    assert_equal(1, pivot_integer(1))
+    assert_equal(-1, pivot_integer(4))
+  end
+end