title: Check if there are no repeats in the list
body: <p>I have a list called com, which contains a bunch of integers. I need to check the list to make sure that each integer only exists once in the list.
  So if:</p>
  
  <pre><code>com{1,2,3,4,1,3}
  </code></pre>
  
  <p>I need have some code to check that 1 is represented twice as well as 3.
  This is my best guess on how to solve it:</p>
  
  <pre><code>for (int j = 0; j &lt; com.Count; j++)
          {
              if (com.Contains(com[j]))
              {
                  lion += 1;
              }
              else
              {
                  lion = 0;
              }   
          }
  </code></pre>
  
  <p>But it doesn't work. Can anybody out there help me??</p>