Merge pull request #803 from fartem/621-Task-Scheduler

2024-12-13 v. 7.3.2: added "621. Task Scheduler"

Author: fartem

README.md

@@ -596,3 +596,4 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 581. Shortest Unsorted Continuous Subarray                      | [Link](https://leetcode.com/problems/shortest-unsorted-continuous-subarray/)                      | [Link](./lib/medium/581_shortest_unsorted_continuous_subarray.rb)                      | [Link](./test/medium/test_581_shortest_unsorted_continuous_subarray.rb)                      |
 | 606. Construct String from Binary Tree                          | [Link](https://leetcode.com/problems/construct-string-from-binary-tree/)                          | [Link](./lib/medium/606_construct_string_from_binary_tree.rb)                          | [Link](./test/medium/test_606_construct_string_from_binary_tree.rb)                          |
 | 609. Find Duplicate File in System                              | [Link](https://leetcode.com/problems/find-duplicate-file-in-system/)                              | [Link](./lib/medium/609_find_duplicate_file_in_system.rb)                              | [Link](./test/medium/test_609_find_duplicate_file_in_system.rb)                              |
+| 621. Task Scheduler                                             | [Link](https://leetcode.com/problems/task-scheduler/)                                             | [Link](./lib/medium/621_task_scheduler.rb)                                             | [Link](./test/medium/test_621_task_scheduler.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 = '7.3.1'
+  s.version = '7.3.2'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/medium/621_task_scheduler.rb

@@ -0,0 +1,26 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/task-scheduler/
+# @param {Character[]} tasks
+# @param {Integer} n
+# @return {Integer}
+def least_interval(tasks, n)
+  count = ::Array.new(128, 0)
+  max = 0
+  max_count = 0
+
+  tasks.each do |task|
+    i = task.ord
+    count[i] += 1
+    c = count[i]
+
+    if c == max
+      max_count += 1
+    elsif c > max
+      max = c
+      max_count = 1
+    end
+  end
+
+  [tasks.size, (max - 1) * (n + 1) + max_count].max
+end

test/medium/test_621_task_scheduler.rb

@@ -0,0 +1,37 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/621_task_scheduler'
+require 'minitest/autorun'
+
+class TaskSchedulerTest < ::Minitest::Test
+  def test_default_one
+    assert_equal(
+      8,
+      least_interval(
+        %w[A A A B B B],
+        2
+      )
+    )
+  end
+
+  def test_default_two
+    assert_equal(
+      6,
+      least_interval(
+        %w[A C A B D B],
+        1
+      )
+    )
+  end
+
+  def test_default_three
+    assert_equal(
+      10,
+      least_interval(
+        %w[A A A B B B],
+        3
+      )
+    )
+  end
+end