title: Deletion of an internal node in 2-3-4 tree
body: <p>I want to delete the 15 from the following 2-3-4 tree. I thought of simply moving the 17 up, but I don't know whether that is correct since it has to be complete.</p>
  
  <p>Delete 15 from the following tree:
  <a href="https://i.stack.imgur.com/FP0AG.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/FP0AG.jpg" alt="enter image description here"></a></p>
  
  <p>How will the 2-3-4 tree look like after deletion? I assume that simply moving up 17 is not correct in this case. But I'm not quite sure.</p>