title: Finding the longest (or all) intersection(s) in word level of two strings in Swift 3
body: <p>Assume two strings:</p>
  
  <ul>
  <li><code>String 1</code>: "Once upon a time there was a beautiful princess named Snow white..."</li>
  <li><code>String 2</code>: "Of course it was a time for a beautiful princess to become one..."</li>
  </ul>
  
  <p>What is the best way to find the longest "intersection" (or all possible intersections) in word level of two strings in Swift? In the previous case it would be: <strong>"a beautiful princess"</strong>.</p>