Re: Extended challenge: Euler's Totient chains Message #22 Posted by Valentin Albillo on 4 June 2012, 6:15 a.m., in response to message #21 by Oliver Unter Ecker
Good morning, Oliver:
Quote:
My quest with PE is a similar one, actually. I set myself the goal to solve half of the PE problems using an interpreted/codemorphing language running on an interpreted language running on a mobile device, which gets me at least a factor of 100 away from C/C++ on a desktop machine.
In that case anything from 10 mins to one hour or two should be considered success. Using a handheld calculator (or emulator thereof) instead of C# running in a multicore desktop is already handicap enough to further compound the situation by requesting physically unrealizable times, so some fair scaling is definitely in order.
Quote:
I'm using the chance to build a language (RPL+) and command set that will allow me to write what I consider elegant code on the user side.
Good luck with that. But I'd (nonpatronizingly) suggest that elegance should play second fiddle to efficiency, which for most PE problems is all but utterly mandatory.
Quote:
Quote:
No, I never visit the solution threads, not interested, this is a completely private endeavour. I just enter my computed result in PE, get the green Ok, and that's it, next problem please.
Really? To me, a good part of the fun is seeing how others accomplished the tasks. I'm regularly amazed at approaches others are taking and learning from it.
Really. I visited the solution threads just once right after solving my very first PE problem (PE 101) in order to see how the threads went, and after a cursory glance decided that I didn't want to see any of it lest I'd spoil both the fun and the learning.
I'll explain: it's not unfrequent that I do manage to solve one of the problems yet I'm not fully satisfied with my approach. Later, I may revisit the problem and come out with a much better approach, all on my own.
That additional satisfaction and the selflearning which comes with it would be completely ruined if I simply looked at the solution threads.
Also, I'm on PE problems strictly for the fun, not to "learn" from others. Any and all learning will be selftaught, by working through a problem to and fro the hard way till I solve it to my complete satisfaction. That's how I learn the most, through sheer effort, and not only do I learn new techniques but also the fine art of finding worthy resources, new books, new articles. Simply looking at other people's solutions, which requires no effort whatsoever, absolutely pales in comparison and is but the easy, lazy approach which, as I said before, just spoils both the fun and the learning.
Quote:
But then, my math knowledge is pitiful and a lot of learning is in order.
I ver much doubt that all too modest assertion but indeed a certain level of math can do wonders for PE problems. Consider PE 276, for instance, which is a truly wonderful problem which can be enunciated in one line and everyone can understand exactly what is asked, yet a straight bruteforce attack is doomed to failure from the start.
If people attempt such primitive approach they'll quickly find out that the problem is O(N^3), thus completely unmanageable. After some thinking and a little math reasoning it's possible to reduce it to O(N^2), which is millions of times faster, yet it would still take a number of months or years to arrive at a solution.
Then, if people's math foundations are solid and sound, they'll eventually find a way to reduce the complexity to O(N), which finally delivers a correct solution in reasonable times (mine was ~19 min). Even better times are still possible but that would be going for the A+.
So yes, improving your math skills is both a prerequisite for and a consequence of PE problemsolving.
Best regards from V.
