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Today's Topics:
1. Re: Performance of Prime Generator (Burton Samograd)
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Message: 1
Date: Mon, 23 Jan 2012 08:30:45 -0700
From: Burton Samograd <[email protected]>
Subject: Re: [Haskell-beginners] Performance of Prime Generator
To: [email protected]
Message-ID: <[email protected]>
Content-Type: text/plain
Zhi-Qiang Lei <[email protected]> writes:
> I have bungled the Prime Generator on SPOJ for many times. Although
> the program is faster and faster on my machine, but it keeps "time
> limited exceeded" on SPOJ (6 seconds limit). Now my approach is for
> every number in the range, check if it is prime by checking if can be
> divided by all the primes smaller than or equal its square root. For
> the numbers between 999900000 and 1000000000, it take 0.64 seconds on
> my laptop. Could anyone give me some hints to enhance it? Thanks.
There are some pretty good examples of fast prime generators here:
http://www.haskell.org/haskellwiki/Prime_numbers
although using them for SPOJ is a bit like cheating :) I learned a lot
from that page though, so I advise giving it a good readover.
--
Burton Samograd
http://kruhft.dyndns.org
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End of Beginners Digest, Vol 43, Issue 28
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