Exercise 12.1.1

For the set of $\{1, 4, 5, 10, 16, 17, 21\}$ of keys, draw binary search trees of heights 2, 3, 4, 5 and 6.

Graphviz is, again, unideal to visualize this, but let's try

Worth noting that heigh is defined so the heigh of a leaf is 0.