title: Find hidden substrings in original string?
body: <p>Hi have a string such as this:</p>
  
  <pre><code>orig = "hbeojllok"
  </code></pre>
  
  <p>And would like to know if there is a specific hidden substring in this string. For example, we can find the word 'hello' in it: <strong>h</strong>b<strong>e</strong>oj<strong>llo</strong>k. We can also find the word 'book': h<strong>b</strong>e<strong>o</strong>jll<strong>ok</strong>. The only constraint is that the letters of the hidden substring have to be in the correct order in the original string. How would I implement this in python? Thank you.</p>