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On the median-of-k versionof Hoare's selection algorithm

Published online by Cambridge University Press:  15 August 2002

Rudolf Grübel
Rudolf Grübel*
Affiliation:
Institut für Mathematische Stochastik, Universität Hannover, Postfach 60 09, 30060 Hannover, Germany; rgrubel@stochastik.uni-hannover.de.
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Abstract

In Hoare's (1961) original version of the algorithm  the partitioning element in the central divide-and-conquer step is chosen uniformly at random from the set S in question.Here we consider a variant where this element is the median of a sample of size 2k+1 from S. We investigate convergencein distribution of the number of comparisons required and obtain a simple explicit result for the limitingaverage performance of the median-of-three version.

Keywords

Randomized algorithmsaverage performanceasymptotic distribution.
Type
Research Article
Information
RAIRO - Theoretical Informatics and Applications , Volume 33 , Issue 2 , March 1999 , pp. 177 - 192
Copyright
© EDP Sciences, 1999

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