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Re: [hackers-il] borrowing CS books

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  • Nadav Har'El
    ... I haven t read that book, so I can t comment on the specific book, but I don t agree about the uselessness of proofs. Besides being an interesting read
    Message 1 of 10 , Nov 4, 2001
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      On Sun, Nov 04, 2001, guy keren wrote about "Re: [hackers-il] borrowing CS books":
      > regarding algorithm books - not sure they are worth buying - when you need
      > to program them, you don't care about proofs (which are large parts of
      > books about algorithms) - rather about the algorithm itself, its purpose
      > and its time/space requirements. and those - you usually have in lecture
      > notes anyway, or you need algorithms that aren't covered by the book.

      I haven't read that book, so I can't comment on the specific book, but I
      don't agree about the uselessness of proofs. Besides being an interesting
      read (well, what do you expect a Mathematician to say ;)), learning how
      existing proofs work will help you one day when you need an algorithm which
      isn't exactly one of the algorithms in the book, and you need to invent your
      own algorithm. After you define your algorithm you need to make sure that it
      indeed does what you want in all cases. I won't lie and say that this happens
      frequently (in most cases you can use existing algorithms, or invent one whose
      proof is "self evident"), but it did happen to me on several occasions
      (especially in the area of graph algorithms).

      Reading those proofs will probably also show you that there's more to life
      than those O(...) numbers: there are typical case numbers, worst-case
      numbers, there are memory-usage issues, and so on. One algorithm can be
      typically faster than another but worse in certain cases (e.g., quick-sort vs.
      heap-sort, if I remember correctly), use more memory but behave differently
      in certain respects (e.g., BFS vs. DFS) and so on.

      Of course, it doesn't mean you need to *buy* that book. Maybe writing good
      notes in class is enough for you for now, and you can buy it (or one of
      the other good books on this subject) later.

      --
      Nadav Har'El | Monday, Nov 5 2001, 19 Heshvan 5762
      nyh@... |-----------------------------------------
      Phone: +972-53-245868, ICQ 13349191 |Unlike Microsoft, a restaurant will give
      http://nadav.harel.org.il |me food for free if I find a bug in it!
    • Dan Kenigsberg
      But to write long essays about algorithms, you do have time... P.S. Maybe my tweak fails on csd for the same reason one of your version kept working on that
      Message 2 of 10 , Nov 4, 2001
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        But to write long essays about algorithms, you do have time...

        P.S. Maybe my tweak fails on csd for the same reason one of your version kept
        working on that computer long after it died anywhere else

        Dan.

        >
        > On Sun, Nov 04, 2001, guy keren wrote about "Re: [hackers-il] borrowing CS books":
        > > regarding algorithm books - not sure they are worth buying - when you need
        > > to program them, you don't care about proofs (which are large parts of
        > > books about algorithms) - rather about the algorithm itself, its purpose
        > > and its time/space requirements. and those - you usually have in lecture
        > > notes anyway, or you need algorithms that aren't covered by the book.
        >
        > I haven't read that book, so I can't comment on the specific book, but I
        > don't agree about the uselessness of proofs. Besides being an interesting
        > read (well, what do you expect a Mathematician to say ;)), learning how
        > existing proofs work will help you one day when you need an algorithm which
        > isn't exactly one of the algorithms in the book, and you need to invent your
        > own algorithm. After you define your algorithm you need to make sure that it
        > indeed does what you want in all cases. I won't lie and say that this happens
        > frequently (in most cases you can use existing algorithms, or invent one whose
        > proof is "self evident"), but it did happen to me on several occasions
        > (especially in the area of graph algorithms).
        >
        > Reading those proofs will probably also show you that there's more to life
        > than those O(...) numbers: there are typical case numbers, worst-case
        > numbers, there are memory-usage issues, and so on. One algorithm can be
        > typically faster than another but worse in certain cases (e.g., quick-sort vs.
        > heap-sort, if I remember correctly), use more memory but behave differently
        > in certain respects (e.g., BFS vs. DFS) and so on.
        >
        > Of course, it doesn't mean you need to *buy* that book. Maybe writing good
        > notes in class is enough for you for now, and you can buy it (or one of
        > the other good books on this subject) later.
        >
        > --
        > Nadav Har'El | Monday, Nov 5 2001, 19 Heshvan 5762
        > nyh@... |-----------------------------------------
        > Phone: +972-53-245868, ICQ 13349191 |Unlike Microsoft, a restaurant will give
        > http://nadav.harel.org.il |me food for free if I find a bug in it!
        >
        >
        > To unsubscribe from this group, send an email to:
        > hackers-il-unsubscribe@egroups.com
        >
        >
        >
        > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
        >
        >
      • Nadav Har'El
        ... Dan, are you sure you really meant for this to appear on the list? ;) I m sure you know the difference between useless emails (what you call essays ) and
        Message 3 of 10 , Nov 4, 2001
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          On Mon, Nov 05, 2001, Dan Kenigsberg wrote about "Re: [hackers-il] borrowing CS books":
          > But to write long essays about algorithms, you do have time...
          >
          > P.S. Maybe my tweak fails on csd for the same reason one of your version kept
          > working on that computer long after it died anywhere else
          >
          > Dan.

          Dan, are you sure you really meant for this to appear on the list? ;)

          I'm sure you know the difference between useless emails (what you call "essays")
          and hacking-sendsms-sessions into the night after a long day. I promise, I'll
          get to that sendsms hacking as soon as possible, hopefully tomorrow night..

          Let's move this issue to private email - I don't think people on this list
          care too much about my work schedule :)

          --
          Nadav Har'El | Monday, Nov 5 2001, 19 Heshvan 5762
          nyh@... |-----------------------------------------
          Phone: +972-53-245868, ICQ 13349191 |If glory comes after death, I'm not in a
          http://nadav.harel.org.il |hurry. (Latin proverb)
        • Nadav Har'El
          ... Please, let s not start with that thread again... The same thing also happened in the linux-il list (for example), without a Reply-To:, because people got
          Message 4 of 10 , Nov 5, 2001
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            On Mon, Nov 05, 2001, Adi Stav wrote about "Re: [hackers-il] borrowing CS books":
            > On Mon, Nov 05, 2001 at 12:43:40AM +0200, Nadav Har'El wrote:
            > > Dan, are you sure you really meant for this to appear on the list? ;)
            >
            > Are we seeing a classic case of Reply-To: overwriting damage?

            Please, let's not start with that thread again... The same thing also happened
            in the linux-il list (for example), without a Reply-To:, because people
            got accustomed to doing "g" (group reply) to answer every email.

            Its just like the people who alias "rm" to "rm -i" to prevent rm accidents,
            and then they get annoyed by rm's question every time, so they become used to
            doing
            \rm file
            when they are "sure" they really want to remove the file. Some time later,
            they \rm a file by accident... A classic case of an arms-race only causing
            bother for normal people, but not solving the original problem.

            *** Vote for Reply-To:!! ***


            --
            Nadav Har'El | Monday, Nov 5 2001, 19 Heshvan 5762
            nyh@... |-----------------------------------------
            Phone: +972-53-245868, ICQ 13349191 |"Never be afraid to tell the world who
            http://nadav.harel.org.il |you are." -- Anonymous
          • Dan Kenigsberg
            ... Nadav, how do these two combine? Anyway, usually I prefer the Reply-To option. But the truly interesting issue in this thread is how come these days I am
            Message 5 of 10 , Nov 5, 2001
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              > > On Mon, Nov 05, 2001 at 12:43:40AM +0200, Nadav Har'El wrote:
              > > > Dan, are you sure you really meant for this to appear on the list? ;)
              > >
              > > Are we seeing a classic case of Reply-To: overwriting damage?
              >
              > Please, let's not start with that thread again...

              > *** Vote for Reply-To:!! ***

              Nadav, how do these two combine?

              Anyway, usually I prefer the Reply-To option. But the truly interesting issue in
              this thread is how come these days I am publicly humiliated in every single
              mailing list I write to.

              Sorry everyone for the annoyance.

              Dan.
            • Adi Stav
              ... Are we seeing a classic case of Reply-To: overwriting damage?
              Message 6 of 10 , Nov 5, 2001
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                On Mon, Nov 05, 2001 at 12:43:40AM +0200, Nadav Har'El wrote:
                > Dan, are you sure you really meant for this to appear on the list? ;)

                Are we seeing a classic case of Reply-To: overwriting damage?
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