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Improved Practical Compact Dynamic Tries

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conference contribution
posted on 10.09.2015, 08:36 by Andreas Poyias, Rajeev Raman
We consider the problem of implementing a dynamic trie with an emphasis on good practical performance. For a trie with n nodes with an alphabet of size σ, the information-theoretic lower bound is nlogσ+O(n) bits. The Bonsai data structure [1] supports trie operations in O(1) expected time (based on assumptions about the behaviour of hash functions). While its practical speed performance is excellent, its space usage of (1+ϵ)n(logσ+O(loglogn)) bits, where ϵ is any constant >0, is not asymptotically optimal. We propose an alternative, m-Bonsai, that uses (1+ϵ)n(logσ+O(1)) bits in expectation, and supports operations in O(1) expected time (again based on assumptions about the behaviour of hash functions). We give a heuristic implementation of m-Bonsai which uses considerably less memory and is slightly faster than the original Bonsai.

History

Citation

Lecture Notes in Computer Science, 2015, 9309, pp. 324-336 (13)

Author affiliation

/Organisation/COLLEGE OF SCIENCE AND ENGINEERING/Department of Computer Science

Source

22nd International Symposium on String Processing and Information Retrieval

Version

AM (Accepted Manuscript)

Published in

Lecture Notes in Computer Science

Publisher

Springer

issn

0302-9743

isbn

978-3-319-23825-8;978-3-319-23826-5

Acceptance date

29/06/2015

Copyright date

2015

Available date

05/09/2016

Publisher version

http://link.springer.com/chapter/10.1007/978-3-319-23826-5_31

Book series

Theoretical Computer Science and General Issues

Language

en

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