Abstract
We introduce and study a problem that we refer to as the optimal split tree problem. The problem generalizes a number of problems including two classical tree construction problems including the Huffman tree problem and the optimal alphabetic tree. We show that the general split tree problem is NP-complete and analyze a greedy algorithm for its solution. We show that a simple modification of the greedy algorithm guarantees O(log n) approximation ratio. We construct an example for which this algorithm achieves Ω \( \Omega \left( {\frac{{\log n}} {{\log \log n}}} \right) \) approximation ratio. We show that if all weights are equal and the optimal split tree is of depth O(log n), then the greedy algorithm guarantees O \( \Omega \left( {\frac{{\log n}} {{\log \log n}}} \right) \) approximation ratio. We also extend our approximation algorithm to the construction of a search tree for partially ordered sets.
Research supported by NSF grant CCR9508545 and ARO grant DAAH04-96-1-0013.
Research supported by the Sloan and Department of Energy Postdoctoral Fellowship for Computational Biology.
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© 1999 Springer-Verlag Berlin Heidelberg
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Kosaraju, S.R., Przytycka, T.M., Borgstrom, R. (1999). On an Optimal Split Tree Problem. In: Dehne, F., Sack, JR., Gupta, A., Tamassia, R. (eds) Algorithms and Data Structures. WADS 1999. Lecture Notes in Computer Science, vol 1663. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-48447-7_17
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DOI: https://doi.org/10.1007/3-540-48447-7_17
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