TIPS and BEST PRACTICES for linked lists
∙ Avoid duplication.
  - Avoid needless special cases.
∙ Draw box-arrow diagrams.
  - Write the step number on the diagram.
∙ Be careful about order.
  - To check yourself, try drawing box-arrow diagram if you flipped two key lines.
∙ Read error message.  Ask for explanation of message if needed.

You are encouraged to post error messages on Piazza.

As always… Do not copy code from lecture or anywhere else, unless explicitly allowed
by instructor (me).  Default is always no copying.