title: quicksort algorithm stability
body: <blockquote>
    <p>Quicksort is not stable, since it exchanges nonadjacent elements.</p>
  </blockquote>
  
  <p>Please help me understanding this statement.</p>
  
  <p>I know  how partitioning works, and what stability is. But I cant figure out what makes the above as the reason for this to be not stable?
  Then I believe the same can be said for merge sort - though it is quoted to be a stable algorithm.</p>