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3:47 AM
Huh, just got my first tag-badge (discussion) on a meta site. Yay?
 
4:02 AM
0
A: Sandbox for Proposed Challenges

QuincunxPossible resistances from resistors code-golf electrical-engineering Meta: Note this is far from done; just putting this idea out so that I can continue working on it. IE way work in progress. I need to specify a lot more of this and I'm putting this here because I know I won't end up working o...

 
 
4 hours later…
8:01 AM
I feel like I have to have this conversation on every single code golf challenge I post: codegolf.stackexchange.com/questions/44333/…
@Geobits Congrats?
 
8:12 AM
hi
 
I got a comment from Peter Taylor saying " I suspect that this may be more trivial than you think.."
not sure what to do with that as I can't find an answer online
0
A: Sandbox for Proposed Challenges

LembikAn input with many outputs Consider two binary strings A and B of length 2x-1 and x, respectively. Now consider a binary output array Z of length x where Z[i] is 1 if B = A[i,...,i+x-1] and 0 otherwise. For a given fixed B, there are a number of different possible output arrays Z. You can find...

he may be right.. I can't tell
 
@Lembik for a start, you could write a brute force reference and test it on small n to see if there's an obvious pattern
This sounds like a pretty interesting challenge:
6
Q: Partitioning with constraints on subsets

Simon WoodsGiven the following data: constraints = {{11, 2}, {11, 3}, {11, 4}, {11, 6}, {11, 9}, {1, 6}, {5, 6}, {2, 5}}; weights = {3, 7, 3, 2, 4, 2, 2, 2, 3, 2, 1}; I wish to partition the integers from 1 to 11 into subsets such that: each integer from 1 to 11 appears exactly once the sum of weights...

@PeterTaylor any idea if an efficient solution is possible?
 
@Lembik Oh right, I forgot to ask - can you put up an example?
For the sandbox question
@MartinBüttner Well let's just hope nobody brings up the "Brainfuck should be 3 bits" problem... :P
 
@Sp3000 If you can show me a codepage which encodes 8-tuples of brainfuck characters in 3 bytes, then I'm all up for it.
 
8:23 AM
Given the hundreds of derivatives on esolangs.org, surely there is one that uses only 3 bits?
 
Hmm, maybe - closest one I know is Golunar, not quite
 
that's only a very slight compression
like 20%
 
If only it used base 95 at least :P
 
here's a 50% compression: esolangs.org/wiki/Binaryfuck
 
Base 32, hmm
 
8:32 AM
oops, 32 is not 64
 
@MartinBüttner From what I gather from the chat log, Nathan's CnR doesn't need cops to have a solution ready, right?
 
@Sp3000 nope
 
Awesome.
 
@MartinBüttner Can't be, surely? With minor tweaks to the values you get a case where every partition of n into pairs is an answer, and that's n! / 2!^(n/2) ~= (n/(e \sqrt 2))^n which is superpolynomial.
 
@PeterTaylor Hm yeah, it's not possible in general, but I'm wondering if the right constraints allow for some substantial speedups.
 
8:42 AM
@Sp3000 sure
 
I can see how to encode the first part as exact multiset cover, but the forbidden constraints are an issue. For practical solution, I would start by finding the legal subsets and then try an exact cover with them.
 
@PeterTaylor very interesting comment!!
@PeterTaylor let me check
@PeterTaylor I mean re: my sandbox question.. I may have just had a bug :(
 
I can make a heuristic argument for why a string of all the same bit should be optimal, but I don't have a proof.
 
assuming your code is correct, maybe one of the many formuations at oeis.org/A000124 would give a proof
I am just checking my clearly broken code
or maybe my problem should be added there :)
 
8:58 AM
@MartinBüttner Well, the constraint {2, 5} is forbidden can be eliminated because it has a total weight of more than 9...
 
@PeterTaylor you are right. the sequence is "The number of length n binary words that have no 0-digits between any pair of consecutive 1-digits. - Jeffrey Liese, Dec 23 2010"
@PeterTaylor I'll change the challenge :)
thank you
 
 
2 hours later…
10:55 AM
@Optimizer How fast is the Java CJam implementation? I haven't tried it myself
 
pretty fast
download it and try
plus, the main time taking part is printing of those many digits on a web page
 
kk will do, now where did Java go...
 
HTML is not good at handling huge string displays
 
Ah that makes sense
Oh that's much faster, thanks
 
11:33 AM
I got such big output that java is not able to handle it
 
:P I don't think Java will handle mine any time soon either
 
12:30 PM
java.lang.RuntimeException: Unhandled char after ':': # :(
 
are you doing :# ?
I am afraid that kissing is not allowed in CJam
 
Damn, there goes my ,:(:# plan :P
 
being sad or happy is allowed, not kissing though
at least 1 form of it ..
 
Can someone judge whether this cracking attempt is correct or not: codegolf.stackexchange.com/a/44469/6638
It was kinda messy
 
12:46 PM
Looking, gimme a sec
Well here's the relevant doc for the print statement
But was the newline part added in after the crack?
(tbh the newline doesn't majorly change the solution, so I don't think it should matter too much)
 
 
2 hours later…
2:56 PM
I liked the idea of user23013's submission, have a hash code that depends on previous character so that you cannot remove any character
The thing that he missed out was the code to convert that hash back to original had so much golfing scope :P
LOL, @ sidebar, the latest what-if of xkcd makes @Geobits a sad panda
2
 
The starred message about it does, though, since the newest one isn't as epic as the one that post was about :(
floating bowling balls < moon swimming
 
@Geobits of course I know that the message about it does
 
I love that they have smartphone controls among the other methods. "Yea, there's an app for that."
 
"You can take down all your enemies with one smile"
that's the best feature of any gadget ever
 
Just don't jump off it when disembarking. That is ill-advised.
 
3:57 PM
Hmmm does CJam take a modulo before applying range?
 
what is the question ?
 
I was trying to do AD#A*48*156#C\7+*,
If you take out the , it's a large number but once you put in the , the range is small
 
so not all are printable, right ?
adding another , to get the actual length of the range
 
I get 84 for the length o_O
 
oh yeah, arrays have a range limit
so yours is modulo that
 
4:03 PM
... damn
 
somehow wrap that big number in an array
and multiply it
 
Hmm that's a good idea
 
4:19 PM
Hmm I feel silly, this isn't what I want to do at all, I'm exponentiating the wrong way around
 
you are powering up the wrong way
 
Yeah :/
Not hard to fix though, at least
 
hi all
I am back after the humiliating defeat of my last sandbox challenge
 
good good
that's the spirit
 
I need to clean out the garbage half written specs I have posted in there
If they were good ideas I probably would have finished them by now
 
4:31 PM
probably
 
5:04 PM
@Doorknob We'll probably delay posting of the current weekly challenge until Monday. Should we start the next round anyway? Or should we just accept that fornightly challenges make more sense on PPCG?
 
this will not be fort night challenge
 
I accept that "fortnightly challenge" sounds way cooler than "weekly challenge", regardless of the practicality of either.
 
yeah , it will miss 2 weekend days
but still, its weekly only.
 
@Optimizer I don't get your point.
My suggestion is to select a new theme only every other week.
 
but why ?
 
5:08 PM
whether the new challenge is then ready after a week, ten days, or two weeks doesn't matter
 
because you think we missed 1 week ? (this week ) ?
 
@Optimizer Because the first challenge took two weeks. The second challenge could have used more than one week to write a reference implementation. And this one didn't meet the single week deadline either.
But I guess my actual answer is "why not?"
 
because "weekly challenge"
 
...
it's not like the entire concept is ruined because you make it every other week.
 
but .. but .. "Weekly Challenge"
 
5:11 PM
@Optimizer It doesn't specify which week the weekly challenge falls on.
 
weekly means every week, no ?
 
Not necessarily. The adverb "weekly" could also be meant to specify how long the challenge runs for.
 
isn't that a week-long challenge?
 
yeah ^ . weekly as an adverb still means once a week
week-lee and week-long
 
The traditional usage of weekly does mean once per week.
 
5:15 PM
I've checked a couple dictionaries online, but can't find one where weekly is listed as having a "week long" definition. That being said, using it this way doesn't really bother me.
 
Gladly doesn't mean once per glad. There's obviously some room for interpretation there.
 
0
A: Sandbox for Proposed Challenges

n̴̖̋h̷͉̃a̷̭̿h̸̡̅ẗ̵̨́d̷̰̀ĥ̷̳A regular expression homework on StackOverflow (Source: http://stackoverflow.com/questions/27988149/find-regular-expressions-of-a-language) code-golf Write 10 regular expressions for the 10 tasks below, each with a different regex flavor. No code execution is allowed in the regex. One of the ...

 
I'm pretty sure that's a bad comparison :D
 
wow. such example. much relation
so wow.
 
This was a triumph
 
5:16 PM
triumph fail
 
Damnit CJam, why won't you do what I want :(
 
because you dont write CJam, CJam makes you write it.
 
wat
 
84 84 84## gives 1 :(
 
in Java interpreter too ?
JS has limits, you know right ?
 
5:21 PM
...oh point
 
just try this in the JS one 84 84 d 84##
 
Nope in the Java interpreter too :/
 
then I think operations on BigInt are not BigInt based
(in CJam)
 
@Sp3000 wat
 
Byte Overflow
 
5:25 PM
Well...
Hm.
Well I guess I'll have to figure this out tomorrow, it's getting late over here
 
You can revert for sure
 
Damn and I thought I was finally up to up-arrow notations :/
 
better than leaving it like that
 
kk, will do
 
@NathanMerrill I preferred the Lunar Swimming what if (or did you post that link before he posted the bowling ball?)
 
5:37 PM
yeah he did b4
 
ah okay
 
tries to see if all answers can fit in 3 characters. question-answer code-golf
 
Wow, I was ninja'd hard on that one. It was there whole minutes before I answered and didn't see it :D
 
what did you two delete ?
 
I answered Martin's question about the sidebar post. Late.
 
5:52 PM
why does hovering over a deleted post still highlight the related reply to post ?
 
They're not hard-deleted (I think mods can still view them), so I guess they just didn't bother to clear/invisify the "repliedTo" field or whatever.
 
yea
 
Someone ruined your comment about the sidebar. Now apparently sandbox comments make a sad panda :(
 
what doesn't make you a sad panda ?
 
Oven-baked macaroni and cheese?
2
 
6:01 PM
1 more upvote to the makes me a sad panda message ...
or the LOL one.
 
I would, but apparently "You cannot star your own messages". Very insensitive to narcissists on SE's part.
A few more stars and some time will push it below the weekly challenge invite :)
 
lol
hmm, weird..
 
6:45 PM
Is there anything wrong with the following approach to the current cop challenge? 1) Golf the crap out of a program, but make sure you use a single variable 11 times. 2) Inflate the name of that variable to something ridiculously long
Assuming you golfed it well, there shouldn't be any way to shorten it in general, and changing the variable name would ensure a distance of >10, right?
Just curious before posting. I've got a program that I'm tweaking, so far up to 9 necessary uses of the variable.
 
@Geobits I swear there used to be a rule that variable names can't be longer than 3 characters, but I don't see it
 
Obviously it's a bit boring, but it seems like it would work (if you make sure it can't be golfed further beside that single name).
Hmm, I've actually got ten uses. Trying to find a way to add it in somewhere else....
 
@Geobits just add it anywhere. removing it also costs more than 10 edits
 
Yea, but commenting it out wouldn't. You could add // and remove 8 chars from the name to get edit distance 10. It needs to be used.
(Or /**/ anyway, since no line breaks)
 
ah fair enough
 
7:01 PM
wow, this is the longest time I have ever taken to get 1000 rep.
 
like... two weeks?
 
still not done , so no idea.
 
Your chart looks relatively steady ;)
Mine is very bumpy by comparison.
 
10 days and only 800 points :(
 
life is hard
 
7:08 PM
and look at that. Martin is again ahead of me for the month !!!!!!!
 
@Optimizer and your bounty total for the month is +50, mine is -150 :P
 
yeah!
:'(
 
also, I'm only ahead because I post challenges... you should try it too :P
 
I am not a creative thinker
my last challenge did not even hit 25 yet.
 
@Optimizer it's not like it can't be practised ;)
 
7:14 PM
practice being creative ? My brain is not made that way ...
I mean my brain does not work properly unless there is a challenge. And it is smart enough to figure out loopholes, so I cannot challenge myself to create a good challenge
 
7:29 PM
@MartinBüttner Winky face in conjuction with double negative is just mean.
 
heh
@Rainbolt I probably have asked you this before, but how come you've never posted an MtG-based golf challenge?
 
I started writing a controller for one actually
The plan was to actually get bots to play MTG against each other
 
a KotH?
that's crazy
 
Bots play chess against each other in order to get better at playing chess. It isn't all that crazy, but it's a bit too large for PPCG
I imagine that you could get quite a few good ideas for "learning" challenges from here youtube.com/view_play_list?p=A89DCFA6ADACE599
The first lecture really hooks you. I strongly advise watching it.
 
7:46 PM
@Rainbolt I've taken Ng's lecture on Coursera.
I found his lectures on youtube during a multimedia analysis seminar a few years ago... he's amazing.
 
I'm only through the first two lectures. And I'm not "taking them" as much as I am watching them lazily.
I never thought someone could drone on for so long and remain interesting the entire time.
 
well yeah, if you do it on coursera there's a bit of coursework as well
 
nice nice
 
Geez, becomes a room owner and just spams a wall of (removed) :P
 
I managed to hold a little monologue in the wrong room
 
7:54 PM
I managed to find 11 places to stash a variable.
Unfortunately, I can only use alphanumeric (and _) to pad variable names in Java.
Otherwise I could get pretty close to the 9500 max
 
8:43 PM
We keep getting burned by Microsoft Word when we copy and past text to code.
She said, “Hello world!” – and here is a dash. // Word
She said, "Hello, world!" - and here is a dash. // Notepad
There should be some sort of feature whereby copying text from Word copies it as the rest of the world would normally write it.
 
@Sp3000 Intrigue was back in stock... just ordered it :)
 
@Rainbolt is there no Paste Special for your requirement?
or is that only Excel... I've not used either for ages
 
9:01 PM
@VisualMelon I was looking for a Copy Special
 
Hmm. Are you sure it's Word's fault and not Notepad's? Notepad mangles non-ASCII text well enough on its own in my experience.
 
Notepad has no issue with the angled quotes.
The top line was originally typed in Word, copied to Notepad. The bottom was typed in Notepad.
 
Oh, I thought the issue was that the angled brackets didn't copy over.
Then yes, I agree. But I'd also say anyone writing code (to later be copied) in Word is just wrong. It's for more documenty things where angled brackets and emdashes are more common.
 
@Rainbolt ah, ok
 
I guess I didn't explain the issue. Customer gives object a name. Developer copies name into code. Name makes it's way into the database. Developer updates code and, in the process, changes long dash to be short dash. Names don't match, and data with the old name is now lost.
And actually that was backwards. More often the case is that we wrote the code with normal characters, and then they complained that it doesn't match exactly so we copy and paste what they wrote straight from Word.
Either way, the characters get out of sync and it's a huge mess.
 
9:09 PM
Sounds like fun.
 
rather
 
You remember sitting in database class thinking "Why does everything have an ID?" Now we know.
 
For indexing, obviously :P
 
That too
Or rather, primarily that
 
all I remember from the Database stuff I've done is "Any non-prime attribute must tell you about the key, the whole key, and nothing but the key, so help me Codd"
which would be useful, if I could remember which Normal Form it applied to
 
9:12 PM
I saw a database once where primary key was name, with the format Last,First. Even thought it was a small table that made collisions unlikely, I died a little inside.
 
If users log into the system with their name, then it makes sense.
 
It was a list of customers :(
This was some years ago, though.
@Rainbolt So have you given up on your tumbleweed or are you just very patient? ;)
 
@Geobits he got it on another site I think
 
^
If this site ever dies I will be here waiting for my tumbleweed.
 
@Rainbolt I'd love to see you post a tips question for the purpose getting tumbleweed though... seems to be the most reliable way
 
9:25 PM
Cool
 
I would inevitable get a comment like "I've never heard of this language before." despite the fact that I posted a link to it.
 
tumbleweed it's s such a weird badge
 
I posted a really difficult challenge once. Some geezer just decided to post his thoughts as a freaking answer.
 
it also has a couple of upvotes...
 
As a side note, I think it is really strange that the challenge got 21 upvotes and only one real answer.
I usually equate hard with unpopular.
 
9:31 PM
let me check what my hardest challenge with a lot of upvotes is
 
Haha I meant to upvote that one the instant it left the sandbox.
 
my latest challenge has 24 upvotes and 1 answer.
that too because i put bounty.
 
Domino Circuits was definitely the most interesting thing I did in 2014
thanks Martin ;)
 
heh, thanks... I wish more people would have found it that interesting... would have been nice to see a few different approaches
 
It's strange when you put so much work into a challenge and one other person gets something out of it. It's almost like you are connected.
 
9:36 PM
I maybe killed it by posting an answer to quickly
 
You did start with "huge, ugly, slow, painful, naughty" to encourage others to post a better solution
 
(it having been in the works for a while before the question was posted)
@Rainbolt I tried!!
I wonder just how strong the correlation between gif content and upvotes is
 
I can tell you now that crudely drawn pictures do not make you famous.
 
it's just because it's not a gif, you should have made is jiggle or change colour or something
 
The art my brother drew for this one got some positive feedback in the comments. But he has a bachelor's degree in Graphic Design from SCAD.
 
9:55 PM
0
A: Sandbox for Proposed Challenges

JakubeEquivalent move sequences on the Rubik's Cube code-golf puzzle-solver A move sequence is a sequence of moves (turns) on a Rubik's Cube (for the notation loow below). For each move sequence, you can find infinite other move sequences, that cause the same results as the original one. In other wor...

 
10:18 PM
@nhahtdh how come you deleted the regex proposal?
 
@Geobits ;)
err
 
@Optimizer are newlines legit?
 
that's not the issue here. but yeah, if you count them to distance ..
I did not even check if mine is shorter.
 
lol
@Optimizer "Your modified code must only have printable ascii."
 
so what if the original code had newlines and I did not change any of them ?
that rule is as absurd as the others ;)
 
10:28 PM
@Optimizer the original code isn't allow to have newlines either
"Only printable ASCII characters are allowed."
 
@MartinBüttner: I can't think of anyway to make it interesting
 
@nhahtdh hm fair enough... I was actually thinking about doing a "golf course" of several regex problems before, but I never bothered coming up with interesting problems that have nice solution which aren't known are pretty short.
when is POPCORN coming then? ;)
@Optimizer I guess, although I think it was posted and cracked before Nathan added the word "printable" to the spec.
 
@MartinBüttner Currently, the solution is going to be more or less the same for any flavor. There are only 2 variations - with lookaround/backref and without lookaround/backref
 
hmm, back to ground zero.
 
10:32 PM
square one?
 
@MartinBüttner Tomorrow, probably
 
@Geobits I remember our database lecturer at uni talking about an organisation which sent her stuff intended for someone else with the same name. She discovered that they were using name as a PK. I can't remember now exactly which organisation it was, but I think it was the ACM. Certainly a computing organisation which should have known better.
 
@nhahtdh kk :)
 
@MartinBüttner: Is the new bonus fine? (also @PeterTaylor)
 
@nhahtdh not using built-in sort?
 
10:35 PM
Yup
 
it's a nice idea, but I'm not sure it'll be worth it in the golfing languages. at least I haven't been able to come up with a nice implementation that wouldn't be substantially longer than the naive approach.
 
@nhahtdh I'm not sure what I should be looking at
 
also, people might just do something like "a = minby(list,bitcount);drop(list,a);print(a)" in a loop to avoid the sorting
 
That will be slow, for millions of elements
I need some timing data, though
To make sure all O(n^2) solutions go down to the drain
 
well, that's my point. there is no mention of a time limit right now, so what's stopping people from using O((2^n)^2) approaches? (I'd love to see an O(n^2) solution btw :P)
 
10:46 PM
Which question are you two talking about?
 
@nhahtdh For GS it's not worth aiming for the bonus, but hey.
 
@PeterTaylor I'm not sure how the easy-to-invert implies that it's trivial to obtain a sequence of moves from two states of the cube.
 
To find the shortest sequence of moves which is equivalent to XYZ, you start from the solved cube, apply the inverse of XYZ, and then solve.
So it's just the older question with a different input format.
Well, actually the older question didn't ask for optimal solutions.
Finding optimal solutions in a reasonable time is quite tough.
 
my point was that you don't have XYZ... or did you actually mean XYZ symbolically, and "then solve [for XYZ]"?
oh
never mind
I get your point
 
10:58 PM
Ok, "equivalent" might have been the wrong word.
There's an easy reduction one way.
 
yeah I was thinking you wouldn't want to do the reduction this way though
because if you already have the move sequence, why go back to a situation where you only have information about the cube states
so I think for golfing this might not be that relevant
 
The move sequence doesn't give you much more than the cube states. This isn't the worst-case situation of the word problem on groups (undecidable) because the group is finite, but there's no a priori reason to expect that any other approach will be better than the reduction.
 
fair enough
 
11:19 PM
@MartinBüttner Huzzah, have fun with Intrigue :D
 
thanks :)
 

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