Quick Sort is very efficient if CUTOFF is the median.

<P>How do we find the median?

<P>All the obvious methods require that we sort L! This is no good!

<P>In practice, people use something that is easier to compute:
<UL>
  <LI>first element
  <LI>mean value
  <LI>median of 3
</UL>

<P><B>Worst case:</B> always pick the smallest element as the CUTOFF.