The Nineteenth Byte

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00:00

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Inspired in part by this Mathologer video on gorgeous visual "shrink" proofs, and my general interest in the topic, this challenge will have you count polygons with integer coordinates in 3D. You'll be provided an input n, which is a non-negative integer. Your program should find the number of su...

New Main Posts

01:38

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Q: Count the Collatz survivors mod 2^n

Introduction We have 22 Collatz conjecture-related challenges as of October 2020, but none of which cares about the restrictions on counter-examples, if any exists, to the conjecture. Considering a variant of the operation defined in the conjecture: $$f(x)= \cases{ \frac{x}{2}&for even x \cr \fr...

code-golf number number-theory

New Sandboxed Posts

02:16

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A: Sandbox for Proposed Challenges

Almost Illegal Strings cops-and-robbers Welcome to a cops and robbers version of Find an Illegal String. An illegal string is "a string of characters that cannot appear in any legal program in your programming language of choice" (from the linked post). For this challenge, we will define an almos...

HyperNeutrino

02:54

so i have a userscript that expands out the flags so i can see them on posts more easily without needing to click on flag history and uh

let's just say that it's not very convenient for viewing the sandbox cuz community autoflags it due to its activity extremely often

Redwolf Programs

Why would that be a reason for autoflag? Does it think it's spam or some sort of voting ring?

HyperNeutrino

i think it just automatically notes questions that have a really high amount of answers posted at once for a moderator to decide if they need to be trimmed/pruned or something like that

Razetime

lot of new users post there as well right

HyperNeutrino

(also it seems that i accidentally clicked the expand button; the userscript just shows the count by default)

yes that is also a reason i think

@NewMainPosts i'm a bit confused; my code and my own calculations by hand seem to suggest that 9 and 30 would also survive the sieve for k=5

Razetime

@NewMainPosts so much comfusement looking at some of these

HyperNeutrino

03:00

since 32a+9 => 48a+14 => 24a+7 => 36a+11 => 54a+17 => 81a+26 which is not less than 32a+9, right?

i'm definitely doing something wrong since this is an OEIS so it's almost certain the sequence isn't wrong and i am

Redwolf Programs

So, I was trying to golf a program to generate DTMF (telephone) tones in class today...I thought I had the volume low enough so that only I could hear it, but it turns out I was slowly driving the class crazy because every few minutes they'd hear a super faint number being dialed, followed by an irregular sounding ringing tone and busy signal.

HyperNeutrino

hahaha oof. yeah, it seems that setting volume low doesn't really work cuz if you can hear it someone close to you will hear it, and the threshold to prevent that is probably between two valid volume settings

headphones are OP but if you wear earbuds your teacher will notice :c

Sisyphus

I can't believe that the 'guess my password' thread is top of HNQ already. Code golf seems to be perfect for gaming SE's hotness formula

(Not that I'm complaining, since it draws users, but still...)

Redwolf Programs

Yeah, lots and lots of positively voted answers

Actually, the HNQ formula seems like it would disadvantage non trivial challenges

Bubbler

03:28

@HyperNeutrino I think it is already excluded by 4a+1, though neither the Q or Wikipedia makes it explicit.

The whole point is that we want to find the smallest counterexample, so if it goes lower at any point, it contradicts itself being the smallest

Razetime

@RedwolfPrograms so you unintentionally pulled off a godlike troll

Redwolf Programs

:p

HyperNeutrino

03:47

I figured out eventually that it's just that rather than being f^x(k)<k it's any f^(a<x)(k)<k. thanks @Bubbler

Bubbler

04:18

And math wins again as always

Razetime

@Bubbler where's da fancy MathJax equation

Bubbler

No equation this time, just fancy fragments sprinkled over the entire post

Lyxal

06:10

@Sisyphus if they don't get closed, pretty much every challenge gets to hot.

caird coinheringaahing

11:22

@Sisyphus Believe it or not, it used to be worse

I had to point out to SE that PPCG had 11 questions in HNQ

Redwolf Programs

13:26

If n is a positive integer, is n^2 / (n - 1) always a positive integer? I think it is, right?

caird coinheringaahing

@RedwolfPrograms Assuming n > 1, yes

Redwolf Programs

Oh, that's cool. It seems to always be n + 1, from what I've seen

Hmm, (n ^ 2) / (n - 1) = (n + 1) -> (n ^ 2) = (n + 1)(n - 1) -> n ^ 2 = n ^ 2 - 1...what did I do wrong?

caird coinheringaahing

Add a one somewhere along the way?

Redwolf Programs

Oh, wait. I'm wrong, that's not always an integer. I was using bigints for testing :p

But (n ^ 2 - 1) / (n - 1) seems to be what I was thinking of

(n ^ 2 - 1) / (n - 1) = (n + 1) -> (n ^ 2) - 1 = (n + 1)(n - 1) -> (n ^ 2) - 1 = (n ^ 2) - 1

That actually seems to be true for every number, where n != 1

Whatever kind of math that is it's much more fun than precalculus

HyperNeutrino

14:14

are answers in non-languages allowed on this site

I can't remember the official policy and I can't seem to find it. maybe i'm just bad at using search functions lol

caird coinheringaahing

@HyperNeutrino As in Text, or Deadfish?

HyperNeutrino

Wolfram Alpha

caird coinheringaahing

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Q: Is Wolfram|Alpha a valid language?

Here are some example code-golf submissions using Wolfram|Alpha: Valentine's golf! I heart you! Largest number in ten bytes of code I have two main questions about the use of Wolfram|Alpha: Is the use of the Internet problematic? What is considered the output? The Internet connectivity con...

discussion

Consensus is "no, as it uses the internet"

HyperNeutrino

ah, okay thanks. i saw that WA is deemed not a valid language but i wasn't sure if submissions are allowed in it cuz i do think i've seen solutions in languages that can't add / can't test primality

i suppose a feature-deficient language is harder and more challenging and getting free internet access is rather boring and bad for the site though

caird coinheringaahing

IIRC languages that can't add/prime test are allowed on kolmo challenges only

HyperNeutrino

14:18

ah okay. most would probably struggle to work on any other challenge but i'll find the consensus if that ever comes up when i'm dealing with flags

thanks

New Sandboxed Posts

15:59

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A: Sandbox for Proposed Challenges

AOG Day 3: Socially Distanced Christmas Plans code-golf math geometry Now that you have your calendar all figured out, it's time to start planning your Christmas celebrations. However, to keep you and your loved ones save, you have to make sure you have enough space for physical distancing (and t...

Razetime

17:22

@HyperNeutrino lotta calendar question for AOG eh

HyperNeutrino

17:41

@Razetime yeah xD i mean it is advent of golf for a reason. also just 2 out of 3 and i plan to make the rest of them reasonably diverse in nature, at least as much as i can

25 is over a quarter of the total challenges i've posted to this site lol

caird coinheringaahing

I reckon organising a PPCG advent calendar of challenges could be a fun idea

Posted by different users of course

HyperNeutrino

I'm in the process of doing that; i tried it a couple of years ago but wasn't able to keep up

caird coinheringaahing

Ooh, here's an idea: find 25 challenges in the Sandbox that have been abandoned, touch them up to site quality and use them

HyperNeutrino

oh that's an interesting idea

caird coinheringaahing

I'd like to do it this year, but given that we'd need to get a list, warn the original authors then select 25 challenges, it might be a bit difficult to do in a month

@HyperNeutrino Yeah, that's why I'm a fan of different users volunteering for it

HyperNeutrino

17:47

Yeah. Last time i started creating them like halfway through november / start of december though, so i don't think i even sandboxed any of them cuz i had to instant-post them

HyperNeutrino

17:57

is there a challenge that's "given an image determine the minimum number of times you need to paint an (axis-aligned) rectangle onto a blank image to obtain it"

@HyperNeutrino yep

Redwolf Programs

19:22

No way, my random Javascript program generator wrote a valid eight digit program with three operators: +4.3 -!4

(It also just defined its first variable, q=2!)

Shaggy

19:45

@RedwolfPrograms you were asking the other day if JS had ever beaten Japt? Behold! codegolf.stackexchange.com/a/66055/58974

Although, that was very early in Japt's lifecycle.

caird coinheringaahing

@Shaggy Guess the Japt answer needs to be updated to take back the crown :P

Neil

also it was @edc65, who was a top JavaScript golfer at the time

Shaggy

@cairdcoinheringaahing Yup, I do intend to give it a go.

New Main Posts

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Q: Get the Systematic Chemical Symbol

Background The systematic symbol is defined as such for \$ 118 < n < 1000 \$: The first letter corresponds to the first digit, capitalized. The second letter corresponds to the second digit. The third letter corresponds to the third digit. This can be generalized for all \$ n > 0\$: For each d...

code-golf string chemistry

Redwolf Programs

20:13

Wait, #! is a valid javascript statement?

caird coinheringaahing

Isn't it a shebang?

Redwolf Programs

Why would anyone put that in a Javascript file though?

caird coinheringaahing

20:55

CMQ: A measure of how successful a challenge is is "Does it have more votes (net) than answers?", and it has a net score of 10 or higher. What percentage of your challenges are successful under this definition?

Furthermore, we can say that you're a successful challenge writer (proven by science¹) if your answer to ^ is >= 50% (because why not?). Are you a successful challenge writer?

HyperNeutrino

21:28

@cairdcoinheringaahing do you mean answer to ^ as in answer to score or answer to (# successful challenges?

wait neither of those make sense. i think i'm entirely misinterpreting lol

caird coinheringaahing

@HyperNeutrino if your percentage of successful challenges is >= 50%

HyperNeutrino

oh wait. you mean "the answer to the above question", not "answer : above" ratio

oops

Lyxal

Morning everyone!

HyperNeutrino

good morning o/

@cairdcoinheringaahing should we include deleted challenges

I have a lot of challenges that would guarantee me to not be a successful challenge writer but they were from when i first joined the site and most have been mopped up by community's roomba

if we don't include deleted challenges, then i am just barely successful (53.1%)

caird coinheringaahing

@HyperNeutrino Since only 10k+ users can see their deleted posts (older than 60 days), I'll go with no

@HyperNeutrino Same :( My first week or so here is the reason I don't have the Curious badge

HyperNeutrino

21:41

@cairdcoinheringaahing wait, if your challenge record goes negative, is it impossible to recover it ever?

Lyxal

I'm at 70.5%, so reasonably successful

caird coinheringaahing

@HyperNeutrino It can't go negative

Lyxal

Then again, two of those aren't code golf

caird coinheringaahing

It's (total questions - closed - negative - deleted) / total questions, so it's always at least non-negative

Lyxal

Non challenges aside, my success rate is 73.3%

HyperNeutrino

21:42

oh, okay cool.

caird coinheringaahing

@Lyxal Challenges don't have to be code golf to be successful (by that definition) :P

HyperNeutrino

data.stackexchange.com/codegolf/query/edit/1314435#resultSets btw

@Lyxal do you mean they're something else like popcons or whatever, or are they tips

Lyxal

@HyperNeutrino tips questions

caird coinheringaahing

Fun fact for those trying to regain their question record, deleted - total - 2*negative - 2*closed tells you how many challenges you need to post (that stay non-closed/deleted/negatively-voted) to regain a record of 0.5 (the requirement for the badge)

HyperNeutrino

oh cool. oh did you post like a really large number of challenges that all got yeeted so now you can't get the badge until you post like a ton more good challenges?

that is unfortunate indeed

caird coinheringaahing

21:48

@HyperNeutrino ...maybe

I may or may not have not heard about the Sandbox and then proceeded to post a bunch of poorly written challenges

HyperNeutrino

feels bad ;-; fortunately i wasn't creative enough to post enough challenges to get myself to that state; i may very well have otherwise, but i posted few enough that i've recovered my record now lmao

Lyxal

22:10

Haha I made an extremely useless verb in J today. Feels good bro

addone =: verb define
y =. y + 1
:
r =. (y - x) * y + x
)

HyperNeutrino

22:31

hey nice :D i've never touched J before, apparently Jelly is similar to J / inspired?

caird coinheringaahing

@HyperNeutrino Yeah, IIRC, Jelly was very inspired by J

HyperNeutrino

J looks interesting but I'm not sure i have the time to learn more golfing languages lol; also if it's similar to Jelly it'll probably not be too helpful both in terms of learning things and golfing

caird coinheringaahing

Honestly, the only reason I can't be bothered to learn J/APL is because Jelly's better, IMO

HyperNeutrino

Jelly is a golfing language so compared to APL it's more golfy in most scenarios (and way less readable or practical xD)

i forget if J is golfing-oriented too

caird coinheringaahing

The massive range of builtins means that when golfing something, my main worry is the algorithm/method, rather than "is it shorter to write it A or B?" which I see a lot with J/APL

HyperNeutrino

22:36

though from what lyxal wrote it seems like it isn't

caird coinheringaahing

@HyperNeutrino Not massively, but it still used to be grouped with golfing languages back when people wanted handicaps on golfscript

HyperNeutrino

@cairdcoinheringaahing Right. and for me learning to write golfy jelly code (after i learned how the heck jelly even worked in the first place lol) was a bit difficult for a while because it's a totally different paradigm/approach to golfing in a practical language, especially coming from a procedural (?) one

Redwolf Programs

Is golfscript even competitive anymore compared to Jelly or 05AB1E?

caird coinheringaahing

@HyperNeutrino Yeah exactly

@RedwolfPrograms Not even close

HyperNeutrino

Oh, okay. yeah it does look very golfy; TBH i had to just look it up otherwise i would've been unsure cuz it always looks so golfy but lyxal's code looks like a "normal" language

caird coinheringaahing

22:38

Jelly > CJam > Golfscript > Perl > Python > Java

if A > B means "A is golfier than B"

@HyperNeutrino Yeah, J and APL are both production languages, they're just so old that their syntax is short and symbolic

HyperNeutrino

oh cool, okay

caird coinheringaahing

@RedwolfPrograms I think you'd be hard-pressed to find a golfscript answer that outgolfs Jelly

New Sandboxed Posts

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A: Sandbox for Proposed Challenges

AOG Day 4: Party Decorations code-golf quine You've figured out exactly how large your room needs to be. However, they only offer rooms in integer side lengths, so looks like calculating the exact dimensions precisely wasn't so necessary. Whoops! You are planning on decorating your wall with an i...

Redwolf Programs

Golfscript is ASCII only, right?

caird coinheringaahing

The commands are, but you can have non-ASCII characters in it

Case in point

Wow, that's the 308th post on the site o.O

caird coinheringaahing

22:54

Any feedback on number 1 or number 2?

Bubbler

23:13

I have posted 83 challenges so far, all of which are open with positive score

I'm so proud of it

rak1507

I haven't posted any, had a few ideas but most of the time someone's already done it :( So hard to come up with original things

Redwolf Programs

23:51

Challenge idea (free for anyone to take): Given an image as input containing regions of white pixels with continuous (always touches in a cardinal direction) black borders one pixel thick, fill each region with a unique color from any adjacent regions. (Similar challenge has been done with ASCII, but still very different)

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