title: How does a regular expression match non-repeating substrings in a string?
body: <p>There is a string:</p>
  
  <pre><code>"1112344866893334". 
  </code></pre>
  
  <p>I want to use regular expressions to match non-repeating substrings like:</p>
  
  <pre><code>"23", "8", "89", "4".
  </code></pre>
  
  <p>How can I do that?</p>