title: Quicksort algorithm using percentiles
body: <p>I was reading on Wikipedia about Quicksort using percentiles <a href="https://en.wikipedia.org/wiki/Quicksort#Using_percentiles" rel="nofollow noreferrer">Link</a> and I didn't understand why when we do a 25-75 split the running time will be O(n log n)? I tried to develop the recursion tree and I didn't have any result.</p>
  <p>Thank you</p>