18.5 Summary

• Binary search trees are simple, but they are subject to imbalance which leads to crappy runtime. 2-3 Trees (B Trees) are balanced, but painful to implement.

• LLRB insertion is simple to implement (deletion is a bit harder to implement, we won't go over the specifics in this course).

  • Use three basic operations to maintain the balanced structure, namely rotateLeft, rotateRight, and color flip.

• LLRBs maintain correspondence with 2-3 trees, Standard Red-Black trees maintain correspondence with 2-3-4 trees.

  • Java’s TreeMap is a red-black tree that corresponds to 2-3-4 trees.

  • 2-3-4 trees allow glue links on either side (see Red-Black Tree).

  • More complex implementation, but faster.