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Article #2916Re: One really good use for BIG core memory
From: David desJardins
Date: Thu, 25 Sep 1986 01:55
Date: Thu, 25 Sep 1986 01:55
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In article <600@sdcc12.UUCP> wa263@sdcc12.UUCP (bookmark) writes: > > I know one really good use for a BIG core memory. There is a >simple O(n) sorting algorithm... suppose we want to sort n elements with >keys ranging in value from 1 to k (k >= n). Just get a big array of k >slots, mark them all with some illegal value, then copy each of the items >to be sorted into the appropriate (k'th) place in the array (this is >called an "address calculation" sort). Then scan the array through and >copy out the items in order. The sort phase is O(n), and the scan phase >takes about constant+(n*otherconst) time, so the whole thing is O(n). The 'scan phase' takes ** O(k) ** time, not O(n). In typical sorting applications k >>> n. If k ~ n, then we already have enough memory for the size k table (if we have enough memory to quicksort the items them- selves!). -- David desJardins
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Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: arc1-ca.pugleaf.net!utzoo!mnetor!seismo!lll-crg!nike!ucbcad!ucbvax!brahms!desj From: desj@brahms.BERKELEY.EDU (David desJardins) Newsgroups: net.arch Subject: Re: One really good use for BIG core memory Message-ID: <15801@ucbvax.BERKELEY.EDU> Date: Wed, 24-Sep-86 21:55:26 EDT Article-I.D.: ucbvax.15801 Posted: Wed Sep 24 21:55:26 1986 Date-Received: Thu, 25-Sep-86 03:43:21 EDT References: <600@sdcc12.UUCP> Sender: usenet@ucbvax.BERKELEY.EDU Reply-To: desj@brahms.UUCP (David desJardins) Organization: University of California, Berkeley Lines: 17