2024-08-20 v. 6.5.1: added "138. Copy List with Random Pointer"

Author: fartem

README.md

@@ -516,3 +516,4 @@ Profile on LeetCode: [fartem](https://leetcode.com/fartem/).
 | 129. Sum Root to Leaf Numbers                                   | [Link](https://leetcode.com/problems/sum-root-to-leaf-numbers/)                                   | [Link](./lib/medium/129_sum_root_to_leaf_numbers.rb)                                   |
 | 133. Clone Graph                                                | [Link](https://leetcode.com/problems/clone-graph/)                                                | [Link](./lib/medium/133_clone_graph.rb)                                                |
 | 134. Gas Station                                                | [Link](https://leetcode.com/problems/gas-station/)                                                | [Link](./lib/medium/134_gas_station.rb)                                                |
+| 138. Copy List with Random Pointer                              | [Link](https://leetcode.com/problems/gas-station/)                                                | [Link](./lib/medium/138_copy_list_with_random_pointer.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 = '6.5.0'
+  s.version = '6.5.1'
   s.license = 'MIT'
   s.files = ::Dir['lib/**/*.rb'] + %w[README.md]
   s.executable = 'leetcode-ruby'

lib/common/list_node_with_random.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+# ListNodeWithRandom implementation for this project
+class ListNodeWithRandom
+  attr_accessor :val, :next, :random
+
+  # @param {Integer} val
+  # @param {ListNodeWithRandom} nxt
+  # @param {ListNodeWithRandom} random
+  def initialize(val, nxt = nil, random = nil)
+    @val = val
+    @next = nxt
+    @random = random
+  end
+
+  # @param {ListNodeWithRandom} l1
+  # @param {ListNodeWithRandom} l2
+  # @return {Boolean}
+  def self.are_equal(l1, l2)
+    while l1 && l2
+      return false if l1.random && l2.random && l1.random.val != l2.random.val
+
+      return false if l1.val != l2.val
+
+      l1 = l1.next
+      l2 = l2.next
+    end
+
+    l1.nil? && l2.nil?
+  end
+end

lib/medium/138_copy_list_with_random_pointer.rb

@@ -0,0 +1,24 @@
+# frozen_string_literal: true
+
+require_relative '../common/list_node_with_random'
+
+# @param {Node} node
+# @return {Node}
+def copy_random_list(head)
+  nodes = {}
+  p = head
+  while p
+    nodes[p] = ::ListNodeWithRandom.new(p.val)
+    p = p.next
+  end
+
+  p = head
+  while p
+    node = nodes[p]
+    node.next = nodes[p.next]
+    node.random = nodes[p.random]
+    p = p.next
+  end
+
+  nodes[head]
+end

test/medium/test_138_copy_list_with_random_pointer.rb

@@ -0,0 +1,74 @@
+# frozen_string_literal: true
+
+require_relative '../test_helper'
+require_relative '../../lib/common/list_node_with_random'
+require_relative '../../lib/medium/138_copy_list_with_random_pointer'
+require 'minitest/autorun'
+
+class CopyListWithRandomPointerTest < ::Minitest::Test
+  def test_default_one
+    first = ::ListNodeWithRandom.new(7)
+    second = ::ListNodeWithRandom.new(13)
+    third = ::ListNodeWithRandom.new(11)
+    fourth = ::ListNodeWithRandom.new(10)
+    fifth = ::ListNodeWithRandom.new(1)
+
+    first.next = second
+    second.next = third
+    third.next = fourth
+    fourth.next = fifth
+
+    second.random = first
+    third.random = fifth
+    fourth.random = third
+    fifth.random = first
+
+    assert(
+      ::ListNodeWithRandom.are_equal(
+        first,
+        copy_random_list(
+          first
+        )
+      )
+    )
+  end
+
+  def test_default_two
+    first = ::ListNodeWithRandom.new(1)
+    second = ::ListNodeWithRandom.new(2)
+
+    first.next = second
+
+    first.random = second
+    second.random = second
+
+    assert(
+      ::ListNodeWithRandom.are_equal(
+        first,
+        copy_random_list(
+          first
+        )
+      )
+    )
+  end
+
+  def test_default_three
+    first = ::ListNodeWithRandom.new(3)
+    second = ::ListNodeWithRandom.new(3)
+    third = ::ListNodeWithRandom.new(3)
+
+    first.next = second
+    second.next = third
+
+    third.random = first
+
+    assert(
+      ::ListNodeWithRandom.are_equal(
+        first,
+        copy_random_list(
+          first
+        )
+      )
+    )
+  end
+end