Search found 533 matches

by jaap
Tue May 28, 2019 12:44 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 672
Replies: 2
Views: 1614

Re: Problem 672

Thanks for fixing that hk. Shouldn't there be a floor function around the $\frac{7^K-1}{11}$ term? I don't think there is a universally accepted meaning for a sum where the upper limit for the index variable is not an integer. Please investigate if $\frac{7^K-1}{11}$ isn't an integer for the values ...
by jaap
Tue May 28, 2019 11:35 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 672
Replies: 2
Views: 1614

Problem 672

Is "no nothing" a typo for "do nothing"?

Shouldn't there be a floor function around the $\frac{7^K-1}{11}$ term? I don't think there is a universally accepted meaning for a sum where the upper limit for the index variable is not an integer.
by jaap
Mon May 27, 2019 12:40 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 671
Replies: 3
Views: 1016

Re: Problem 671

I have not solved this question yet, but have worked out F_4(3) on paper. @amagri: I believe those are indeed forbidden, so for both those reasons you cannot use a 1x3 tile when n=3. @MuthuVeerappanR: I think rotations around the axis of the loop are not considered different. I get 24+24+24+24+8 = 1...
by jaap
Mon May 20, 2019 12:31 am
Forum: News, Suggestions, and FAQ
Topic: Recover account
Replies: 4
Views: 351

Re: Recover account

hk wrote:
Sun May 19, 2019 11:55 am
I looked up your account:
Last Visit:

Saturday, 19th May 2018, 11:11 pm
So it seems that you remembered your password after all.

(usually people find out their password after some head scratching.)
It is 2019 now, you know.
by jaap
Fri May 17, 2019 5:36 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 647
Replies: 2
Views: 840

Re: Problem 647

I know that quite some folk have solved this one already and it doesn't look too daunting, really - except that: well I'm getting 186 and not 184 as result for F_3(100). It really is 184. If you want, you can send me the pairs (A,B) that make up the sum by private message (you should have only four...
by jaap
Sat Mar 16, 2019 8:59 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 600
Replies: 1
Views: 175

Re: Problem 600

RichardDL wrote:
Sat Mar 16, 2019 4:13 pm
18, 5, 1, 4, 3, 3, 2
18, 5, 2, 3, 3, 4, 1
Hexagons that are mirror images of one another are congruent.
by jaap
Wed Mar 06, 2019 4:21 pm
Forum: News, Suggestions, and FAQ
Topic: Project Euler Style Sheet Update
Replies: 33
Views: 3129

Re: Project Euler Style Sheet Update

First, I don't know how to switch from the dark theme to light or vice versa. Is this missing, hidden, or am I just blind? In the Account tab, there is a section with Country, Language etc, including Theme. Change the Theme from Dark to Default (and click the Update Details button) to go back to wh...
by jaap
Mon Mar 04, 2019 9:30 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 425
Replies: 28
Views: 5752

Re: Problem 425

pxor wrote:
Mon Mar 04, 2019 4:03 am
Hey, could anyone explain how is 503 connected to 2?
503 is connected to 103, and the rest is via the chain given as an example in the problem:
2 ↔ 3 ↔ 13 ↔ 113 ↔ 103 ↔ 503
by jaap
Wed Feb 20, 2019 10:57 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 656
Replies: 9
Views: 654

Re: Problem 656

In the wording of the problem, I don't think it is a good idea to use the letter n for two different variables - first as the index of the sequence, then as an element of T. I think it would be better to change the second use to a variable named t for example.
by jaap
Sat Jan 12, 2019 10:00 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 196
Replies: 34
Views: 9217

Re: Problem 196

tchiari wrote:
Sat Jan 12, 2019 6:53 pm
I'm wondering if someone would be willing to give me a prime that is part of a triple but not on my list. That would help me to figure out if the issue is with how I'm generating/determining my primes or with how I'm looking for triples.
I've sent a private message.
by jaap
Mon Dec 24, 2018 5:49 am
Forum: News, Suggestions, and FAQ
Topic: Hairsplitting Curiosity (w/ Alliteration)...
Replies: 6
Views: 1259

Re: Hairsplitting Curiosity (w/ Alliteration)...

https://projecteuler.net/about=aliases If you hover over a poster's name in a solution thread (specifically the ones that are in italics, which indicates it is an alias), you will see a tooltip showing the account username. Unfortunately the quoting system always seems to display the username, not i...
by jaap
Sat Dec 15, 2018 5:48 am
Forum: Discrete Mathematics
Topic: Sorting...
Replies: 4
Views: 2550

Re: Sorting...

You have re-invented the Pigeonhole sort.

The wiki page on sorting algorithms has a separate section for non-comparison integer sorts like this. Its main disadvantage is that its running time and its memory requirements depend on max, not just on n.
by jaap
Fri Nov 16, 2018 3:47 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 351
Replies: 13
Views: 6973

Re: Problem 351

If you ever need more than, say, 600MB of data, then you are probably doing it wrong. You are either using the wrong solving method, or maybe you just don't need to have all of that data in memory at the same time.
by jaap
Fri Nov 16, 2018 2:09 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 351
Replies: 13
Views: 6973

Re: Problem 351

Cheers Jaap, I'm afraid I'll have to confess my ignorance on the first question (I'll google that though). I do use vectors, yes, but I would have thought it would pose problems of efficiency too as it will take up a lot of memory. I'll try that approach over the weekend though and see what happens...
by jaap
Fri Nov 16, 2018 1:33 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 640
Replies: 7
Views: 2346

Re: Problem 640

LarryBlake wrote:
Fri Nov 16, 2018 12:55 pm
@jaap, may I PM you my assumptions and a question? I believe I'm having the same difficulty tuple describes.
Sure, go ahead.
by jaap
Fri Nov 16, 2018 10:31 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 351
Replies: 13
Views: 6973

Re: Problem 351

On my system and using C/C++, defining an array this size immediately causes a 'Segmentation fault' - and the number spaces required only get larger on some of the more difficult problems on PE. Am I missing something? Do you know the difference between the stack and heap memory? Do you know how to...
by jaap
Thu Nov 08, 2018 10:30 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 640
Replies: 7
Views: 2346

Re: Problem 640

It seems I'm having the same problem as tuple, as I get those answers too.

Edit: Solved it now. I had made an assumption that was not true in every situation, and from reading the problem's thread, many others did so too.
by jaap
Wed Oct 17, 2018 8:46 am
Forum: Number
Topic: "Fixed Points"
Replies: 5
Views: 5384

Re: "Fixed Points"

Oh, it's the unmistakable work of Raymond Smullyan. The strings we are working with are expressions. Just like an ordinary arithmetical expression like "4+5" can be evaluated to yield "9", these strings have their own type of arithmetic that can be used to evaluate them and yield another string. You...
by jaap
Tue Oct 16, 2018 6:30 am
Forum: Number
Topic: "Fixed Points"
Replies: 5
Views: 5384

Re: "Fixed Points"

kenbrooker wrote:
Mon Oct 15, 2018 9:47 pm
In this case, X is a string and X is a function, a function of itself.
In what case? In what context do you have strings that are also functions?

It is hard to tell what misunderstandings you might have if you don't show the original text that you might be misunderstanding.