title: Quicksort - conditions that makes it stable
body: <p><strong>A sorting algorithm is stable if it preserves the relative order of any two elements with equals keys. Under which conditions is quicksort stable?</strong></p>
  
  <p>Quicksort is stable when no item is passed unless it has a smaller key. </p>
  
  <p>What other conditions make it stable?</p>