copy-list-with-random-pointer.md

<p>A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null.</p>

<p>Return a <a href="https://en.wikipedia.org/wiki/Object_copying#Deep_copy" target="_blank"><strong>deep copy</strong></a> of the list.</p>

<p>&nbsp;</p>

<p><strong>Example 1:</strong></p>

<p><strong><img alt="" src="https://discuss.leetcode.com/uploads/files/1470150906153-2yxeznm.png" style="width: 375px; height: 129px;" /></strong></p>

<pre>
<strong>Input:
</strong><span id="example-input-1-1">{&quot;$id&quot;:&quot;1&quot;,&quot;next&quot;:{&quot;$id&quot;:&quot;2&quot;,&quot;next&quot;:null,&quot;random&quot;:{&quot;$ref&quot;:&quot;2&quot;},&quot;val&quot;:2},&quot;random&quot;:{&quot;$ref&quot;:&quot;2&quot;},&quot;val&quot;:1}
</span>
<b>Explanation:
</b>Node 1&#39;s value is 1, both of its next and random pointer points to Node 2.
Node 2&#39;s value is 2, its next pointer points to null and its random pointer points to itself.
</pre>

<p>&nbsp;</p>

<p><strong>Note:</strong></p>

<ol>
	<li>You must return the <strong>copy of the given head</strong>&nbsp;as a reference to the cloned list.</li>
</ol>