Ruby Solution 1

1# Definition for Node.
2# class Node
3#     attr_accessor :val, :next, :random
4#     def initialize(val = 0)
5#         @val = val
6#		  @next = nil
7#		  @random = nil
8#     end
9# end
10
11# @param {Node} node
12# @return {Node}
13def copyRandomList(head)    
14  curr = head
15  copy_head = head.clone
16  copy_curr = copy_head
17
18  random_list = {}
19  random_list[head.object_id.to_s.to_sym] = copy_head
20
21  # copy next
22  while curr
23    curr = curr.next
24    copy_curr.next = curr.clone if curr
25    copy_curr = copy_curr.next
26    random_list[curr.object_id.to_s.to_sym] = copy_curr if copy_curr
27  end
28
29  # copy random
30  curr = head
31  copy_curr = copy_head
32  while curr 
33    copy_curr.random = random_list[curr.random.object_id.to_s.to_sym] if curr.random
34    curr = curr.next
35    copy_curr = copy_curr.next
36  end
37
38  copy_head
39end

Ruby Solution 2

1def copyRandomList(head)
2  copy_head = Marshal.load(Marshal.dump(head))
3end