Generate all combinations of string in PHP : <p>I'm trying to generate all possible combinations of a string using PHP. I've searched this site for a while trying to find the right algorithm but I can't seem to find the correct one. To be more specific if i input the string "hi", I want it to return "hi", "ih", "h", "i". But I don't want it to reuse the same characters multiple times. So I wouldn't want "hh" and "ii". Is there an algorithm for this? Thanks!  </p>
