From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=0.2 required=5.0 tests=BAYES_00,INVALID_MSGID, REPLYTO_WITHOUT_TO_CC autolearn=no autolearn_force=no version=3.4.4 X-Google-Language: ENGLISH,ASCII-7-bit X-Google-Thread: 109fba,baaf5f793d03d420 X-Google-Attributes: gid109fba,public X-Google-Thread: fc89c,97188312486d4578 X-Google-Attributes: gidfc89c,public X-Google-Thread: 103376,97188312486d4578 X-Google-Attributes: gid103376,public X-Google-Thread: 1014db,6154de2e240de72a X-Google-Attributes: gid1014db,public From: Lawrence Kirby Subject: Re: Teaching sorts [was Re: What's the best language to start with?] Date: 1996/09/02 Message-ID: <841700695snz@genesis.demon.co.uk>#1/1 X-Deja-AN: 178074016 x-nntp-posting-host: genesis.demon.co.uk references: <4vtto9$77n@goanna.cs.rmit.edu.au> x-mail2news-path: genesis.demon.co.uk organization: none reply-to: fred@genesis.demon.co.uk newsgroups: comp.lang.c,comp.lang.c++,comp.unix.programmer,comp.lang.ada Date: 1996-09-02T00:00:00+00:00 List-Id: In article <4vtto9$77n@goanna.cs.rmit.edu.au> ok@goanna.cs.rmit.edu.au "Richard A. O'Keefe" writes: >dewar@cs.nyu.edu (Robert Dewar) writes: > >>Richard said >>"There is another factor: heap sort requires moving one's attention from >>card [i] to card [i/2]; this is a very expensive operation for people". > >>Oh gosh no!!! > >>Arrange the cards in a heap layed (sic) out as a binary tree, nothing else >>makes sense if you are using heap sort on cards. Remember that the >>[i] to [i/2] business is just a trick for mapping the underlying binary >>tree! That's how I approached it originally. The problem with this is that the cards near the apex of the heap are physically a long way apart and it takes longer to move them. >A very fair point, which I must concede. >It does, however, support my contention, which is that the costs for people >may differ from the costs for computers, and different spatial layouts of >the cards may very large difference to human costs, thus making manual card >sorting a rather poor way to gain intuition about *computer* costs. However it is still a good way of getting to know the algorithm. If you can apply an algorithm to different situations where different operations are available with different costs then you know the algorithm well. >Animations such as those on the Cormen Leiserson & Rivest CD may perhaps >be a better way to go. Possibly although I haven't seen them. The important thing for learning is to perform the steps yourself. -- ----------------------------------------- Lawrence Kirby | fred@genesis.demon.co.uk Wilts, England | 70734.126@compuserve.com -----------------------------------------