title: Quick Sort Average and Worst case complexity confusion?
body: <p>I am a little confused regarding the Average and Worst Case of Quick sort. I know the following:</p>
  
  <ol>
  <li>Quick sort has average case complexity of O(nlogn) when the middle pivot is chosen.</li>
  <li>Quick sort Worst case complexity is when the Minimum or Maximum element is chosen as the pivot.</li>
  <li>Both the above cases will provide the same complexity for a almost sorted list of elements and a list of unsorted data.</li>
  </ol>
  
  <p>Are the above three points true? If not I would like to know how Quick sort would behave for an almost sorted list and an unsorted list?</p>