Red-Black Properties
The red-black properties:
1. Every node is either red or black
2. Every leaf (NULL pointer) is black
- Note: this means every “real” node has 2 children
3. If a node is red, both children are black
- Note: can’t have 2 consecutive reds on a path
4. Every path from node to descendent leaf contains the same number of black nodes
5. The root is always black