title: How can I find all possible letter combinations of a string?
body: <p>I am given a string and i need to find all possible letter combinations of this string. What is the best way I can achieve this?
  example:</p>
  
  <pre><code>abc
  </code></pre>
  
  <p>result:</p>
  
  <pre><code>abc
  acb
  bca
  bac
  cab
  cba
  </code></pre>
  
  <p>i have nothing so far. i am not asking for code. i am just asking for the best way to do it? an algorithm? a pseudocode? maybe a discussion?</p>