title: When does introsort shift from quicksort to heapsort?
body: <p><a href="http://en.wikipedia.org/wiki/Introsort" rel="nofollow">Introsort</a> begins with quicksort and switches to heapsort when the recursion depth exceeds a level based on the number of elements being sorted.  What is that number?  Is there a specific range or a limiting value?</p>