Search found 23 matches

by philiplu
Wed Dec 18, 2019 7:51 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 037
Replies: 45
Views: 10807

Re: Problem 037

@Junglemath, I posted an explanation in the forum, though you've since deleted your questions. Guess you figured it out before I finished my post :)
by philiplu
Wed Dec 11, 2019 8:24 pm
Forum: Resources
Topic: Nim Problems
Replies: 1
Views: 429

Re: Nim Problems

If you search on "Stone Game" you'll find a few more Nim-style games: 260 Stone Game 70% 325 Stone Game II 80% 366 Stone Game III 40% 550 Divisor Game 55% There are many others which turn out to be impartial games using Sprague-Grundy, but I won't point those out since it's not always as obvious tha...
by philiplu
Mon Nov 25, 2019 7:22 am
Forum: News, Suggestions, and FAQ
Topic: New awards.
Replies: 68
Views: 23154

Re: New awards.

Thanks, @euler. I really like the idea of the two awards, with one for hitting half the levels. That answers the big reservation I had about my suggested award, which would be too oriented toward those already in the advanced levels.
by philiplu
Tue Oct 22, 2019 12:45 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 009
Replies: 47
Views: 12941

Re: Problem #9

No, and in fact they couldn't possibly be. If a, b, c are all consecutive, then a+b+c = a+(a+1)+(a+2) = 3a+3, which is a multiple of 3. 1000 is not a multiple of 3, so it can't be the sum of 3 consecutive integers.
by philiplu
Mon Aug 26, 2019 3:47 am
Forum: News, Suggestions, and FAQ
Topic: Statistics Levels no longer works
Replies: 2
Views: 408

Re: Statistics Levels no longer works

Until it's fixed, you can still go directly to the page for a specific level, e.g. https://projecteuler.net/level=5
by philiplu
Tue Jun 25, 2019 6:17 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 674
Replies: 1
Views: 3462

Re: Problem 674

My solution didn't look to see if any two lines were the same, so I'd say (1) you're to count the two lines of "va" as two distinct I-expressions and (2) order doesn't matter when pairing up lines, so only look at one of the two possible orderings.
by philiplu
Mon Apr 22, 2019 6:49 am
Forum: Clarifications on Project Euler Problems
Topic: Clarification on Project Euler Problems...
Replies: 2
Views: 1267

Re: Clarification on Project Euler Problems...

They're both prime, so certain useful theorems in modular arithmetic which require either a prime or coprime modulus will work (intentionally not saying what those are - plenty of problems revolve around discovering those). Also, they're below $2^{30}$, so if you compute $a*b \pmod{1000000007}$, whe...
by philiplu
Wed Apr 03, 2019 9:51 pm
Forum: News, Suggestions, and FAQ
Topic: New awards.
Replies: 68
Views: 23154

Re: New awards.

Not sure how open the team is to adding new awards, but since the recent website updates, at least the array of awards flows better as the number of awards changes. So here's an idea I've had for a while. How about an award for solving at least 1 problem in all 20 possible difficulty levels? I'm a b...
by philiplu
Tue Nov 13, 2018 8:07 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 521
Replies: 9
Views: 4236

Re: Problem 521

vamsikal3 wrote:
Tue Nov 13, 2018 3:57 am
Can someone verify the answer for n = 201820182018 is <snipped by moderator>? Thanks!
Those are the correct final 9 digits.
by philiplu
Wed Nov 07, 2018 9:56 pm
Forum: Clarifications on Project Euler Problems
Topic: Problem 640
Replies: 7
Views: 3204

Re: Problem 640

Your values for N=2 or 3 are correct. The rest are incorrect.
by philiplu
Thu May 03, 2018 7:58 am
Forum: Clarifications on Project Euler Problems
Topic: Problem 200
Replies: 23
Views: 6874

Re: Problem 200

Could anyone post a number that ends with either 1 or 3 or 7 or 9 (i.e., one of those numbers is in its units place) that is prime-proof? It does not have to be a sqube let alone one that contains 200. If you've solved the problem, take a look at my post from 15 Jan 2018. I ran through the first 10...
by philiplu
Thu Apr 26, 2018 4:23 am
Forum: News, Suggestions, and FAQ
Topic: Localizing custom MathJax macros & commands
Replies: 0
Views: 2956

Localizing custom MathJax macros & commands

You can define new macros in MathJax, e.g. \def\D{{\mathbb{D}}} to create a shortcut \D to display $\mathbb{D}$. The problem is that will affect the rest of the current page, bleeding into following posts. Is there a way to localize such definitions? I see that MathJax has a \begingroup..\endgroup c...
by philiplu
Sun Apr 22, 2018 2:40 pm
Forum: News, Suggestions, and FAQ
Topic: Errors/Warnings/Bugs
Replies: 527
Views: 110172

Re: Errors/Warnings/Bugs

I've got a post here on the latest problem, 625, that looks fine on Windows browsers (Chrome, Firefox, Edge), but was garbled under Safari on iOS (up-to-date 2017-vintage iPad and an iPhone 5S). There were double-dollar delimited LaTex expressions, tagged 4 and 6, where the following text was missin...
by philiplu
Wed Feb 14, 2018 6:18 am
Forum: News, Suggestions, and FAQ
Topic: Collapsible text section suggestion
Replies: 8
Views: 2291

Re: Collapsible text section suggestion

Thanks again for implementing the collapse BBCode. Don't want to sound ungrateful, but I'm seeing behavior which might be intentional or just a bug. I can't nest other BBCodes inside a collapse block. I wanted to use collapse around an image, so the image wouldn't take excessive space, but it didn't...
by philiplu
Sun Feb 11, 2018 10:31 pm
Forum: News, Suggestions, and FAQ
Topic: Collapsible text section suggestion
Replies: 8
Views: 2291

Re: Collapsible text section suggestion

You can see the use case I had in mind in my reworked 31 Jan 2018 post in Problem 209 (View Problem). The new BBCode reduces my post from way too long to just wordy. Brevity, alas, may be beyond me. :)
by philiplu
Sun Feb 11, 2018 8:09 am
Forum: News, Suggestions, and FAQ
Topic: Collapsible text section suggestion
Replies: 8
Views: 2291

Re: Collapsible text section suggestion

Whoa, I hadn't noticed my suggestion had been implemented. Very nice - and I like the ability to title the collapsed block. Thanks indeed, euler.
by philiplu
Tue Jan 30, 2018 9:31 am
Forum: News, Suggestions, and FAQ
Topic: Collapsible text section suggestion
Replies: 8
Views: 2291

Collapsible text section suggestion

I'd like to post something fairly involved in a problem forum, but want it to be normally collapsed in the same way as code blocks. Unlike a code block, though, I'd like to post with the normal formatting available. In particular, I'd like MathJAX to work. The use case is when I want to include a le...
by philiplu
Tue Jan 23, 2018 8:04 pm
Forum: News, Suggestions, and FAQ
Topic: You cannot make double posts error
Replies: 3
Views: 1779

Re: You cannot make double posts error

Looks like this is happening again. I tried to post to problem 194's forum and got an error when I submitted. My progress page reports I have a post up for 194, but it's not visible, and any attempt to post a new reply gives me the "double post" message. Did my post make it to the DB and this is a c...
by philiplu
Sun Dec 03, 2017 1:30 am
Forum: News, Suggestions, and FAQ
Topic: Difficulty Rating for New Problems
Replies: 20
Views: 3440

Re: Difficulty Rating for New Problems

Hmm, I guess that means Poohsticks Marathon, 589 was supposed to be easy, given the standard posting cadence? If it makes you feel better, I did assess this one as Medium, but was out-voted. It's one of those that depends on you having mastered a technique from earlier in the problem set. Eh, that'...
by philiplu
Sat Dec 02, 2017 9:34 pm
Forum: News, Suggestions, and FAQ
Topic: Difficulty Rating for New Problems
Replies: 20
Views: 3440

Re: Difficulty Rating for New Problems

Hmm, I guess that means Poohsticks Marathon, Problem 589 (View Problem) was supposed to be easy, given the standard posting cadence? Well, that's discouraging :shock:. That one's been kicking my butt for a month now :). I could solve it if the one-minute rule was loosened to, say, a one-year rule.