title: Find last duplicate character from string
body: <p>I have a string <code>abbccdeefght</code>,I want to find the last duplicate character from the string.
  For above string the result should be character 'e'.
  I tried using <code>Counter</code> from <code>collections</code> module in python.</p>
  
  <pre><code>from collections import Counter
  c=Counter('abbccdeefght')
  c
  
  &gt;&gt;&gt; Counter({'c': 2, 'b': 2, 'e': 2, 'a': 1, 'd': 1, 'g': 1, 'f': 1, 'h': 1, 't': 1})
  </code></pre>
  
  <p>but not sure how to proceed</p>