Search found 179 matches

by quilan
Mon Nov 14, 2011 10:16 pm
Forum: Number
Topic: Chinese remainder theorem with exponents
Replies: 1
Views: 3544

Re: Chinese remainder theorem with exponents

Duality wrote:I'd love to see more examples of how this works -- there's not a whole lot out on the net that explains it very well
I'm not really sure what you mean with this. Could you go into more detail with what you're asking about?
by quilan
Wed Nov 09, 2011 10:30 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 356
Replies: 17
Views: 7014

Re: Problem 356

sivakd wrote:I am hoping this is not going to give out much. For me, the research I did to solve problem 318 helped in solving this.
I could kiss you right now. I'm as blind & dumb as a bat, I swear to god. I have no idea how I missed behavior that obvious! I'll have it solved shortly!
by quilan
Tue Nov 08, 2011 7:19 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 356
Replies: 17
Views: 7014

Re: Problem 356

So, I've been completely unsuccessfully ramming my head against this problem for weeks now and I'm curious about one thing: Is the typical method of solution specific to the nature of the root of a cubic? Or could you come up with a method to solve (for instance) $ \lfloor1.1^a\rfloor (mod \; b) $ a...
by quilan
Sun Oct 09, 2011 11:26 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 352
Replies: 35
Views: 11587

Re: Problem 352

Thank you :) the second case is what threw me off ... there's actually a direct formula for calculating it. Sorry for the stupid question though, but what do you mean by "it"? The expected value? Posterior probability of any single one being infected? I have a formula, too. It's just got capital si...
by quilan
Sun Oct 09, 2011 5:50 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 352
Replies: 35
Views: 11587

Re: Problem 352

My thinking goes I only need to take care of two possibilities: 1 - Where we don't know if any are infected *uniform* 2 - Where we know at least one is infected The first case is straight forward, but for the second case I literally go through all the possibilities: WhatIfOneIsInfected * ChanceOnly...
by quilan
Fri Oct 07, 2011 12:06 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 352
Replies: 35
Views: 11587

Re: Problem 352

Well this is fun. First problem I've sat down to tackle in a while and I've got a great algorithm going that I know is correct (both T(25,0.02) and T(25,0.10) are spot on the nose, and tactically it makes perfect sense). The only problem is that when I do the full problem, I get an invalid answer. W...
by quilan
Thu Jun 09, 2011 3:36 pm
Forum: Recreational
Topic: Suggested Careers that involve PE type thinking
Replies: 2
Views: 3449

Re: Suggested Careers that involve PE type thinking

Well, I work at a company that creates image processing software (specifically the recognition section of the company, i.e. OCR, ICR, Barcode, etc). I can say with authority that the tricks & algorithms I've learned throughout PE have given me a big boost in coming up with top-of-the-line techniques...
by quilan
Thu Jun 09, 2011 3:30 pm
Forum: News, Suggestions, and FAQ
Topic: Are all new problems difficult ones?
Replies: 6
Views: 3299

Re: Are all new problems difficult ones?

Yeah, it's very much a sliding metric of difficulty. Things that might have been considered 'hard' back in the earlier problems are easy compared to the later problems. It's mainly that doing all of these problems trains you in techniques & problem solving, so something that would have been hard bef...
by quilan
Thu Jun 02, 2011 3:45 pm
Forum: News, Suggestions, and FAQ
Topic: Only a small critique
Replies: 2
Views: 1421

Re: Only a small critique

You're not exactly narrowing down that field... which particular graphic is poor? All of them? General web design?
by quilan
Sun May 29, 2011 5:10 pm
Forum: News, Suggestions, and FAQ
Topic: Spurious Incorrect Confirmation Code error?
Replies: 4
Views: 2164

Re: Spurious Incorrect Confirmation Code error?

Protip -- click the number box to have it auto-refresh without having to reload the page. I always do that before submitting an answer.
by quilan
Tue May 24, 2011 3:20 pm
Forum: Programming languages
Topic: PHP is too powerless for PE?
Replies: 11
Views: 8075

Re: PHP is too powerless for PE?

The brute force approach will work for some of the earlier problems; god knows it helped me more than once when I was beginning this site & didn't understand a lot of the more advanced mathematical / algorithmic methods one can use in later problems. You'll find that the numbers for the later proble...
by quilan
Sun May 22, 2011 4:14 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 339
Replies: 27
Views: 7353

Re: Problem 339

Doh, I came here for the exact same reason. I have no idea how I passed over the opposite color distinction, even though I'd read the passage twice. Selective blindness I suppose.
by quilan
Sat May 21, 2011 4:58 am
Forum: Programming languages
Topic: Python 3 IDE
Replies: 8
Views: 8751

Re: Python 3 IDE

Hello all, I currently use PyScripter IDE for coding in Python 2 and 3 in Windows, but I also use Ubuntu, in which I only use DrPython to code only Python 2. I was wondering if anyone knows any lightweight Python 3 IDEs for Ubuntu. All I really want is customisable syntax highlighting and an inbuil...
by quilan
Tue May 10, 2011 2:43 am
Forum: Applied Mathematics
Topic: Absorbing Markov chains... how do they work?
Replies: 1
Views: 7429

Re: Absorbing Markov chains... how do they work?

AHAH! I think I figured it out! if $ N = (I-Q)^{-1} $, the correct values are $ \frac { N^2R } { NR } $, where it's element-wise division of the upper & lower matrices. Derivation: Given a transition matrix $ M = \left[ \begin{array}{cc} Q & R \\ 0 & I \end{array} \right] $ Expected value is: $ E[X]...
by quilan
Tue May 10, 2011 1:40 am
Forum: Applied Mathematics
Topic: Absorbing Markov chains... how do they work?
Replies: 1
Views: 7429

Absorbing Markov chains... how do they work?

So I've used Markov chains plenty before, but only in the case of one absorbing state. I was playing around with a super simple example of a random walk, and I got really confused by the results. The simple random walk is: [x] <- [a] <-> -> [y] with equal probabilities in each direction. In canonica...
by quilan
Fri Jan 21, 2011 6:39 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 319
Replies: 23
Views: 7734

Re: Problem 319

quintana wrote:could t(30) possibly end up with ...9113247?
thanks!
This is incorrect -- you're very close though. ....3243.
by quilan
Thu Jun 10, 2010 1:30 am
Forum: News, Suggestions, and FAQ
Topic: integer limits and 1 minute rule
Replies: 5
Views: 1849

Re: integer limits and 1 minute rule

Thanks again. I just checked with the IT Manager. It is most likely my computer is a 32-bit integer machine. It's not that; many/most languages feature 64-bit data types even on 32-bit integer machines. VBA on the other hand, only really has the Currency type that's 64-bit and the Decimal type that...
by quilan
Thu Jun 10, 2010 12:47 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 280
Replies: 9
Views: 3630

Re: Problem 280

Ok, so I think I've got a handle on the maths required for this, but my very very simple brute force simulation is producing some odd values. So, starting from the middle square: 00000 00000 00X00 00000 11111 would the actual expected value of the number of turns it takes to reach the N'th item on t...
by quilan
Thu Jun 03, 2010 12:15 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 059
Replies: 95
Views: 22793

Re: Problem 059

I'm not sure if I understand corectly. The cipher text is made of symbols C1, C2, ..... Cn. (in this case n=1201) The original text is made of symbols O1, O2, ..... On. The password is made only of 3 symbols, namely S1, S2 and S3. And the original text must be made by these formulae O1=C1xorS1 ; O2...
by quilan
Wed May 19, 2010 1:39 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 258
Replies: 22
Views: 7326

Re: Problem 258

I do have the same problem that quilan had: I solved the problem (in very LONG runtime) and gained access to the forum, but I have no idea, why the method i.e. of the first post is working. Could some kindly soul PM me some hints for further reading? I'll send some info once I get into work this mo...