We present a novel connection between binary search trees (BSTs) and points in the plane satisfying a simple property. Using this correspondence, we achieve the following results: 1. A surprisingly clean restatement in geometric terms of many results and conjectures relating to BSTs and dynamic optimality. 2. A new lower bound for searching in the BST model, which subsumes the previous two known bounds of Wilber [FOCS'86]. 3. The first proposal for dynamic optimality not based on splay trees. A natural greedy but offline algorithm was presented by Lucas [1988], and independently by Munro [2000], and was conjectured to be an (additive) approximation of the best binary search tree. We show that there exists an equal-cost online algorithm, transforming the conjecture of Lucas and Munro into the conjecture that the greedy algorithm is dynamically optimal. Copyright © by SIAM.
CITATION STYLE
Demaine, E. D., Harmon, D., Iacono, J., Kane, D., & Pǎtraşcu, M. (2009). The geometry of binary search trees. In Proceedings of the Annual ACM-SIAM Symposium on Discrete Algorithms (pp. 496–505). Association for Computing Machinery (ACM). https://doi.org/10.1137/1.9781611973068.55
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