title: Shortest regex for binary number with even number of 0s or odd number of 1s
body: <p>Write an expression that contains an even number of 0s or an odd number of 1s</p>
  <p>I got it down to:</p>
  <pre class="lang-none prettyprint-override"><code>1*(01*01*)* + 0*10*(10*10*)*
  </code></pre>
  <p>where the first part represents an even number of 0s and the second part an odd number of 1s</p>
  <p>However, there's supposed to be a simplified solution that I'm not seeing. Any tips?</p>