title: Remove only first instance of a character from a list of characters
body: <p>Here's what I want to do. I have 2 strings and I want to determine if one string is a permutation of another. I was thinking to simply remove the characters from string A from string B to determine if any characters are left. If no, then it passes.</p>
  <p>However, I need to make sure that only 1 instance of each letter is removed (not all occurrences) unless there are multiple letters in the word.</p>
  <p>An example:</p>
  <blockquote>
  <p>String A: cant</p>
  <p>String B: connect</p>
  <p>Result: -o-nec-</p>
  </blockquote>
  <p>Experimenting with NSString and NSScanner has yielded no results so far.</p>