2025-02-17 v. 8.5.8: added "1396. Design Underground System"

Author: fartem

README.md

@@ -690,6 +690,7 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 1382. Balance a Binary Search Tree                                                  | [Link](https://leetcode.com/problems/balance-a-binary-search-tree/)                                                  | [Link](./lib/medium/1382_balance_a_binary_search_tree.rb)                                                  | [Link](./test/medium/test_1382_balance_a_binary_search_tree.rb)                                                  |
 | 1387. Sort Integers by The Power Value                                              | [Link](https://leetcode.com/problems/sort-integers-by-the-power-value/)                                              | [Link](./lib/medium/1387_sort_integers_by_the_power_value.rb)                                              | [Link](./test/medium/test_1387_sort_integers_by_the_power_value.rb)                                              |
 | 1395. Count Number of Teams                                                         | [Link](https://leetcode.com/problems/count-number-of-teams/)                                                         | [Link](./lib/medium/1395_count_number_of_teams.rb)                                                         | [Link](./test/medium/test_1395_count_number_of_teams.rb)                                                         |
+| 1396. Design Underground System                                                     | [Link](https://leetcode.com/problems/design-underground-system/)                                                     | [Link](./lib/medium/1396_design_underground_system.rb)                                                     | [Link](./test/medium/test_1396_design_underground_system.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)                                    |
 | 2425. Bitwise XOR of All Pairings                                                   | [Link](https://leetcode.com/problems/bitwise-xor-of-all-pairings/)                                                   | [Link](./lib/medium/2425_bitwise_xor_of_all_pairings.rb)                                                   | [Link](./test/medium/test_2425_bitwise_xor_of_all_pairings.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 = '8.5.7'
+  s.version = '8.5.8'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/medium/1396_design_underground_system.rb

@@ -0,0 +1,41 @@
+# frozen_string_literal: true
+
+# https://leetcode.com/problems/design-underground-system/
+class UndergroundSystem
+  # Init
+  def initialize
+    @stations = {}
+    @check_ins = {}
+  end
+
+  # @param {Integer} id
+  # @param {String} station_name
+  # @param {Integer} t
+  # @return {Void}
+  def check_in(id, station_name, t)
+    @check_ins[id] = { station_name: station_name, time: t }
+  end
+
+  # @param {Integer} id
+  # @param {String} station_name
+  # @param {Integer} t
+  # @return {Void}
+  def check_out(id, station_name, t)
+    check_in = @check_ins.delete(id)
+
+    name = "#{check_in[:station_name]} -> #{station_name}"
+
+    @stations[name] = [] unless @stations.include?(name)
+
+    @stations[name] << t - check_in[:time]
+  end
+
+  # @param {String} start_station
+  # @param {String} end_station
+  # @return {Float}
+  def get_average_time(start_station, end_station)
+    times = @stations["#{start_station} -> #{end_station}"]
+
+    times.sum.to_f / times.size
+  end
+end

test/medium/test_1396_design_underground_system.rb

@@ -0,0 +1,92 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/medium/1396_design_underground_system'
+require 'minitest/autorun'
+
+class DesignUndergroundSystemTest < ::Minitest::Test
+  def test_default_one
+    underground_system = ::UndergroundSystem.new
+
+    underground_system.check_in(45, 'Leyton', 3)
+    underground_system.check_in(32, 'Paradise', 8)
+    underground_system.check_in(27, 'Leyton', 10)
+
+    underground_system.check_out(45, 'Waterloo', 15)
+    underground_system.check_out(27, 'Waterloo', 20)
+    underground_system.check_out(32, 'Cambridge', 22)
+
+    assert_in_delta(
+      14.00000,
+      underground_system.get_average_time(
+        'Paradise',
+        'Cambridge'
+      )
+    )
+
+    assert_in_delta(
+      11.00000,
+      underground_system.get_average_time(
+        'Leyton',
+        'Waterloo'
+      )
+    )
+
+    underground_system.check_in(10, 'Leyton', 24)
+
+    assert_in_delta(
+      11.00000,
+      underground_system.get_average_time(
+        'Leyton',
+        'Waterloo'
+      )
+    )
+
+    underground_system.check_out(10, 'Waterloo', 38)
+
+    assert_in_delta(
+      12.00000,
+      underground_system.get_average_time(
+        'Leyton',
+        'Waterloo'
+      )
+    )
+  end
+
+  def test_default_two
+    underground_system = ::UndergroundSystem.new
+
+    underground_system.check_in(10, 'Leyton', 3)
+    underground_system.check_out(10, 'Paradise', 8)
+
+    assert_in_delta(
+      5.00000,
+      underground_system.get_average_time(
+        'Leyton',
+        'Paradise'
+      )
+    )
+
+    underground_system.check_in(5, 'Leyton', 10)
+    underground_system.check_out(5, 'Paradise', 16)
+
+    assert_in_delta(
+      5.50000,
+      underground_system.get_average_time(
+        'Leyton',
+        'Paradise'
+      )
+    )
+
+    underground_system.check_in(2, 'Leyton', 21)
+    underground_system.check_out(2, 'Paradise', 30)
+
+    assert_in_delta(
+      6.66667,
+      underground_system.get_average_time(
+        'Leyton',
+        'Paradise'
+      )
+    )
+  end
+end