Article View: comp.lang.misc
Article #2164Re: A very brief history of optimal sorting methods
From: Anton Rang
Date: Sun, 18 Nov 1990 20:00
Date: Sun, 18 Nov 1990 20:00
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Arrggh. I know I'm going to regret getting into this thread.
In article <237@smds.UUCP> rh@smds.UUCP (Richard Harter) writes:
>One time only, I'll try to make it very simple. If you do a radix sort
>you make multiple passes over the data. In each pass you move all of the
>records. The minimum number of passes needed is log(N) where N is the
>number of records and the base of the logarithm is the bin size. N*log(N)
>records must be moved. Is that clear enough?
Are we assuming that the radix sort uses a fixed amount of auxiliary
storage? If you sort using pointers, the time would be made up of:
* The number of passes, which is at most the number of bytes/key;
(replace 'byte' by a storage unit for your favorite base)
Times the number of keys, since you're sorting all the records;
Times the size of a pointer, since you're moving the pointers.
This is O(bytes/key) * O(number of keys) * size of pointer.
(If pointers are not fixed-length, this isn't linear; if they
are, it's linear in the number of bytes.)
* The time to rearrange records, which is obviously linear in the
number of bytes.
Am I missing something here? The original messages aren't on my news
system any more. Is there an explanation of the algorithm being
discussed published somewhere?
Anton
+---------------------------+------------------+-------------+
| Anton Rang (grad student) | rang@cs.wisc.edu | UW--Madison |
+---------------------------+------------------+-------------+
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<5488@lanl.gov> <6913:Nov1008:23:5690@kramden.acf.nyu.edu> <16709:Nov1113:56:2390@kramden.acf.nyu.edu> <237@smds.UUCP>Show Full Headers
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!wuarchive!zaphod.mps.ohio-state.edu!unix.cis.pitt.edu!dsinc!netnews.upenn.edu!msuinfo!rang From: rang@cs.wisc.edu (Anton Rang) Newsgroups: comp.lang.misc Subject: Re: A very brief history of optimal sorting methods Message-ID: <RANG.90Nov18150047@nexus.cs.wisc.edu> Date: 18 Nov 90 20:00:47 GMT References: <5488@lanl.gov> <6913:Nov1008:23:5690@kramden.acf.nyu.edu> <16709:Nov1113:56:2390@kramden.acf.nyu.edu> <237@smds.UUCP> Sender: news@msuinfo.cl.msu.edu Organization: UW-Madison CS department Lines: 30 In-Reply-To: rh@smds.UUCP's message of 12 Nov 90 07:35:22 GMT