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Author Dietzfelbinger, Martin ♦ Hhne, Martin ♦ Weidling, Christoph
Source ACM Digital Library
Content type Text
Publisher Association for Computing Machinery (ACM)
File Format PDF
Copyright Year ©2008
Language English
Subject Domain (in DDC) Computer science, information & general works ♦ Computer programming, programs & data
Subject Keyword Data structures ♦ Dictionaries ♦ Dynamic hashing ♦ Hash functions ♦ Implementation
Abstract We describe experimental results on an implementation of a dynamic dictionary. The basis of our implementation is “dynamic perfect hashing” as described by Dietzfelbinger et al. (SIAM J. Computing 23, 1994, pp. 738--761), an extension of the storage scheme proposed by Fredman et al. (J. ACM 31, 1984, pp. 538--544). At the top level, a hash function is used to partition the keys to be stored into several sets. On the second level, there is a perfect hash function for each of these sets. This technique guarantees $\textit{O}(1)$ worst-case time for lookup and expected $\textit{O}(1)$ amortized time for insertion and deletion, while only linear space is required. We study the practical performance of dynamic perfect hashing and describe improvements of the basic scheme. The focus is on the choice of the hash function (both for integer and string keys), on the efficiency of rehashing, on the handling of small buckets, and on the space requirements of the implementation.
ISSN 10846654
Age Range 18 to 22 years ♦ above 22 year
Educational Use Research
Education Level UG and PG
Learning Resource Type Article
Publisher Date 2008-06-12
Publisher Place New York
e-ISSN 10846654
Journal Journal of Experimental Algorithmics (JEA)
Volume Number 12
Page Count 25
Starting Page 1
Ending Page 25


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Source: ACM Digital Library