title: Hashset in array of array in c#?
body: <p>I have this code:</p>
  <pre><code>        HashSet&lt;int&gt; arr = new HashSet&lt;int&gt; { 1, 1, 2 };
  
          HashSet&lt;List&lt;int&gt;&gt; arrOfarr = new HashSet&lt;List&lt;int&gt;&gt;();
          arrOfarr.Add(new List&lt;int&gt; { 1,2,3 });
          arrOfarr.Add(new List&lt;int&gt; { 1,2,3 });
  </code></pre>
  <p>Due to <strong>arr</strong> is a Hashset so obviously it returns {1,2} but I am wondering why <strong>arrOfarr</strong> returns both similar arrays. How does it works? How to change that to not return duplicate arrays?</p>