Need a way to find the middle value efficiently.
A linked list is no good for this.
Design using L = 1 3 4 6 8 9 11.
The 1st thing we need is a pointer to the middle element: 6. What should 6 point to? There are 2 possible outcomes that involve further search: X < 6 and X > 6.
Similarly for 6 and 9:
Binary tree such that for each node:
