Awesome! Good to know someone here is not only into Project Euler, but also very close to Level 3! I am slowly inching towards Level 2. I ran into the same issues with Problem #66 as well; when a 8-core machine couldn't handle it, I can stop beating up on my MacBook Air for failing to finish :-) Looking forward to reach the Expert and Legend level on Project Euler with some paired-problem solving in the future! Cheers,
Prakash N Murthy http://twitter.com/_prakash --- On Wed, 8/25/10, Gavin Kistner <[email protected]> wrote: From: Gavin Kistner <[email protected]> Subject: Re: [Boulder Ruby Group] Any Project Euler enthusiasts in the area? To: "Prakash N Murthy" <[email protected]> Cc: [email protected] Date: Wednesday, August 25, 2010, 4:39 PM On Aug 24, 2010, at 11:04 PM, Prakash N Murthy <[email protected]> wrote: I came across Project Euler recently as a good way to learn Ruby; solving the mathematical problems there has been very addictive! Ran into issues with some of the problems where my brute-force method of programmatically analyzing every possible path/option did not work- the program ran for more than a day before I lost patience. So was wondering if anyone one else in this group has been bitten by this bug before and could suggest some alternate approaches to these problems. A couple of problems that I have difficulty solving:Problem 12: What is the value of the first triangle number to have over five hundred divisors? Problem 44: Find the smallest pair of pentagonal numbers whose sum and difference is pentagonal. I and a coworker here have been fighting the Euler fight for several years now (only 13 problems to go for Level 3!) using Ruby. Apparently we have solved both of your problems, but unfortunately we didn't start keeping copies of the Ruby scripts around until semi-recently. I'll have a go at them again with the 'help' of the forum answers and reply to you privately if I get something. FWIW, an embarrassing number of recent 'wins' have been achieved not through elegance or insight, but by parallelizing the solution and running 7 copies on my 8-core work machine until it finishes. :p Sadly/thankfully, I think we've finally hit problems where this order-of-magnitude gain--and our willingness to sometimes wait overnight for a solution--are no longer sufficient. For example, our latest brute-force attempt at problem #66 ran over the weekend and got stuck on step 149/1000.-- (-, /\ \/ / /\/
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