title: Python - not subscriptable
body: <p>I get error TypeError: 'int' object is not subscriptable
  what should I do to fix it?</p>
  
  <pre><code>def permutation(k, s):
      r = s[:]
      for j in range(2, len(s)+1):
          r[j-1], r[k%j] = r[k%j], r[j-1]
          k = k/j+1
          return r
  </code></pre>