On parallel hashing and integer sorting

Yossi Matias, Uzi Vishkin

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

19 Scopus citations

Abstract

The problem of sorting n integers from a restricted range [1..m], where m is superpolynomial in n, is considered. An o(n log n) time randomized algorithm is given. Our algorithm takes O(n log log m) expected time and O(n) space. (Thus, for m=npolylog(n) we have an O(n log log n) time algorithm.) The algorithm is parallelizable. The resulting parallel algorithm achieves optimal speed up. Some features of the algorithm make us believe that it is relevant for practical applications. A result of independent interest is a parallel hashing technique. The expected construction time is logarithmic using an optimal number of processors, and searching for a value takes O(1) time in the worst case. This technique enables drastic reduction of space requirements for the price of using randomness. Applicability of the technique is demonstrated for the parallel sorting algorithm, and for some parallel string matching algorithms. The parallel sorting algorithm is designed for a strong and non standard model of parallel computation. Efficient simulations of the strong model on a CRCW PRAM are introduced. One of the simulations even achieves optimal speed up. This is probably a first optimal speed up simulation of a certain kind.

Original languageEnglish
Title of host publicationAutomata, Languages and Programming - l7th International Colloquium, Proceedings
EditorsMichael S. Paterson
PublisherSpringer Verlag
Pages729-743
Number of pages15
ISBN (Print)9783540528265
DOIs
StatePublished - 1990
Event17th International Colloquium on Automata, Languages and Programming, 1990 - Warwick, United Kingdom
Duration: 16 Jul 199020 Jul 1990

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume443 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349

Conference

Conference17th International Colloquium on Automata, Languages and Programming, 1990
Country/TerritoryUnited Kingdom
CityWarwick
Period16/07/9020/07/90

Funding

FundersFunder number
National Science FoundationCCR-890649
Office of Naval ResearchN00014-85-0046

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