The Nineteenth Byte

El'endia Starman

01:15

@flawr Ta-da!

Leaky Nun

02:00

CMC: Let a[0] = 2 and a[n+1] = 2 ** a[n] - 1. Find the first n such that a[n] is composite

Bubbler

@LeakyNun Wait, is that Chat Mega Challenge?

El'endia Starman

I was thinking Fermat primes, actually.

Hmm, close but not quite. Goes like 2, 3, 7, 63. Hey, found it!

Bubbler

@El'endiaStarman Nope, next of 7 is 127, and then 2^127-1

And then 2^(2^(2^127-1)-1)-1 is still prime

El'endia Starman

Ah shoot, went to 2**6 - 1 not 2**7 - 1.

Does this have a name?

Bubbler

@LeakyNun You're asking to solve Catalan-Mersenne number conjecture

Veskah

02:11

He's trying to Good Will Hunting us while pocketing the credit

Anonymous

The trick to Leaky's CMCs is not to solve them (because they're often impossible or big open questions), but rather to identify why it's not feasible to solve them

Veskah

So we shouldn't believe his lies, gotcha

Anonymous

Are you doing more movie references there?

Veskah

I may or may not be

lirtosiast

02:37

@Bubbler I don't see anything about M M M 127 being prime

Veskah

02:53

Those some spooky looking ascii-art challenges on the front page

Bubbler

03:17

@lirtosiast Um, I seemingly mixed up this OEIS entry with the Wikipedia article

Zacharý

Instead of Good Will Hunting, I'd think of Tom Lehrer's Plagiarize

(a song)

lirtosiast

05:41

slant.co/options/128/alternatives/~brainfuck-alternatives

This website lists "20 best alternatives to Brainfuck" and they're all just real programming languages

FrownyFrog

it’s autogenerated

obviously

it just lists the programming languages that have a high PRO to CON ratio

New Main Posts

07:11

0

Q: Prime containment numbers (golf edition)

This is sequence A054261. The \$n\$th prime containment number is the lowest number which contains the first \$n\$ prime numbers as substrings. For example, the number \$235\$ is the lowest number which contains the first 3 primes as substrings, making it the 3rd prime containment number. It i...

New Main Posts

07:27

0

Q: Prime containment numbers (speed edition)

This is sequence A054261 The \$n\$th prime containment number is the lowest number which contains the first \$n\$ prime numbers as substrings. For example, the number \$235\$ is the lowest number which contains the first 3 primes as substrings, making it the 3rd prime containment number. It is...

math primes integer fastest-code

New Sandboxed Posts

07:39

0

A: Sandbox for Proposed Challenges

Angle from x-axis Given 2 points in a 2-D cartesian coordinate system, find the angle made between the line joining them and the x-axis. Rules The input 2 points can be taken in any convenient format. [(2,3),(4,5)] The co-ordinates can be any rational numbers. Output must be in degrees with ...

mınxomaτ

Wooh, GitHub Actions (integrated CI) is in beta.

maxb

08:00

@user202729 It's your lucky day, I also created a fastest-code version of my challenge.

Downgoat

08:17

@mınxomaτ as in the dev api?

oh I am just still on waitlist D:

maxb

09:00

Should fastest-code challenges accept an answer after a certain time, or is that up to the person who made the challenge? There doesn't seem to be a consensus from what I've seen

Also, thanks @Skidsdev for coming up with the idea of posting both a golfing and a fastest-code version of your Arbitrary randomness challenge. I really like the concept, I hope you don't mind that I used that format for my challenge.

mınxomaτ

I'm evaluating (fast) perceptual hashing algorithms. Which one of these sets is better in your opinion: pste.eu/p/IZxU.html ? The images are sorted by similarity.

maxb

@mınxomaτ I'd probably say the lower one, though it seems that they find different things.

For visualization, I think a cluster graph could be more helpful to visualize distances between images. Something like this perhaps?

user202729

10:39

@Anush OCR is a well-known problem, so... Besides, there are actually existing tools that (claim to, didn't test) do it.

@NewMainPosts TBH I'm not really interested in making a program.

maxb

13:28

@user202729 In that case, what was your idea for the implementation? Right now my fastest solution is actually string-based, only casting to int to compare which number is bigger

Adám

Hm, just wrote an O(nⁿ) function. That's so bad Wikipedia doesn't even list it…

user202729

@maxb All strings have small length.

Neil

@Adám is that significantly worse than O(n!)?

user202729

@Neil Consider n! ~ (n/e)^n, so e^n times worse.

maxb

@Neil For input n=10, it's about 3000 times worse

Neil

13:37

sure, but is eⁿ significant compared to n!?

user202729

Obviously not.

maxb

@Adám The obvious question becomes: why and how did you write a O(n^n) function?

Adám

@maxb Finding permutations by generating all combinations and filtering those that are permutations. It literally contains the code 1…nⁿ.

maxb

@Adám Was it in a golfing challenge, or something else? For golfing it's almost encouraged

Adám

@maxb Yeah, of course. Even infanticide is fine to save a byte, right?

maxb

13:51

@user202729 I used that fact in my solution, combined with the fact that some strings can be substrings of other substrings

@Adám I'd put all the blame on the programmer who implemented a 1-byte literal for that.

Adám

@maxb I think it takes two: 👶︎💀︎

maxb

@Adám haha, good thing MathGolf doesn't have that yet. It's 100% Geneva Convention compatible (so far)

Zacharý

14:07

Lol

Adám

14:36

Language design is on-topic when no golfing discussion are ongoing, right?

maxb

@Adám I won't tell if you won't

Fatalize

Pretty much everything should be on-topic considering the lack of activity on TNB nowadays

Adám

Any kind of feedback on this proposal is appreciated.

Fatalize

(what's up with the Viking ship logo?)

Adám

@Fatalize You mean that it makes no sense at all?

Fatalize

14:42

I'm not saying it doesn't, I'm saying I don't get it if there is one

Adám

@Fatalize Dyalog (for some reason, maybe to honour its Danish management) uses Viking themed logos for its user meetings. When they run out of one subject of logos, they switch to a new one, but I think this time they ran out of ships and had to make one up. ⍨

Fatalize

I see

I don't know much about APL, but from what I see of the comparison examples given, the proposal is much more readable for a non-expert

Zacharý

14:57

Yeah, rather than using mix and reshape for everything.

Skidsdev

15:14

y'know, if I fixed all the bugs in braingolf it'd be a decent language for some challenges...

Zacharý

Same with RAD, if I actually fix bid and will on it, it's be decent

Skidsdev

it's always nice to see a Braingolf answer in the wild

AdmBorkBork

You know you've made it as a language designer when someone uses your language in a submission. You know you've made it as a good language designer when someone uses your language in a submission and you go "How does that work?"

Skidsdev

15:38

haha

either that or your language is just really esoteric

a few people have used braingolf here before, I know @totallyhalloween has a couple of times

but I have yet to see a submission to which my response is "How the fuck does that work"

I mean I've had a few "huh I wonder how that works" reactions, but I can usually figure it out pretty quickly cos braingolf is basic af

I'm torn right now: 1) Fix Braingolf bugs 2) Remake 2col 3) Fix Sum-It bugs 4) Expand on LMBM 5) Finish Funcsational

I have way too many languages

and the only one that I can safely call complete is brainflump

Zacharý

Hey, you're not cairdcoinheringaahing, doesn't he have like dozens of languages

Skidsdev

15:53

brainflump was a collab between he and I :P

New Main Posts

16:12

0

Q: Writing polyglot for Esolang?

How could you write a polyglot in a way that, if ran by brainfuck will give output as brainfuck and ran by piet will give output as piet?

code-challenge polyglot puzzle-solver brainfuck

Pavel

CMP: / 2 or >> 1?

user202729

/ 2u.

(/2 requires adding the sign bit before shifting so is slightly slower, >>1 may have unexpected priority. If the number may be negative then they're not equivalent)

Erik the Outgolfer

@Adám bottom-right of that thumbnail is a bit disturbing, tbh...

it looks like you are some haunted being :P no offense

Zacharý

/2, one less byte

Skidsdev

@Pavel CMP?

Pavel

16:27

@Skidsdev Chat Mini Poll

Skidsdev

>> 1 would only work for unsigned integer types, no?

user202729

@Skidsdev s/work/same result as \/2/

Pavel

jshell> -2>>1
$1 ==> -1

jshell> -2/1
$2 ==> -2

jshell> -8>>1
$3 ==> -4

jshell> -3>>1
$4 ==> -2

jshell> -3/2
$5 ==> -1

user202729

wait it's not c :/

Anyway,

Pavel

In Java, at least, >> rounds down and / rounds towards 0

IDK how C does it tbh

user202729

16:29

@Pavel s/up/down/g

Skidsdev

No thats rounding up

Pavel

Yes

Skidsdev

-1.5 to -1 is rounding up

Pavel

Negative numbers are hard ok

They don't even exist

user202729

@Pavel They're all two's complement, behavior is identical.

Skidsdev

16:30

Ok so >> 1 and / 2 in Java would only have the same result for positive numbers, right?

because for positive numbers rounding towards 0 is rounding down

user202729

@Skidsdev And multiple of 2.

(info: for int32_t x, x/2 is (x+(x>>31))>>1 for gcc)

Pavel

Is >>1 faster than /2?

user202729

For signed, yes.

For unsigned, usually no, but depends on compiler.

Pavel

Compiler will probably optimize constant 2 division when appropriate anyway, I suppose

Skidsdev

benchmark for "Is your language fast enough": Can your language, given an infinite loop outputting a single ascii character each time, fill up TIO's output buffer in under 60 seconds?

user202729

16:38

I guess yes. Even c++ can.

Skidsdev

I mean of course a real language can

I'm referring more to interpreted esolangs

as long as your language can print an ascii char and re-loop 2.184 times per millisecond, it'll fill up the buffer in under 60 seconds

that's 0.4578 ms per loop

Dennis

Assuming said esolang has infinite loops and explicit I/O.

New Sandboxed Posts

0

A: Sandbox for Proposed Challenges

Solve TSP. You're given an oracle that solves maximum independent set in O(n^3). Fastest algorithm win. SN: If the solution is likely to be trivial, maybe code-golf

quartata

@Pavel always, but even the worst compiler on the planet will do the optimization

Skidsdev

@Dennis of course

dzaima

16:43

canvas succeeds in 10s but it doesn't give output live, so ¯\_(ツ)_/¯

quartata

@user202729 ?

user202729

@quartata What can't you understand?

quartata

arthimetic vs logical shifts isnt much of a point of comparison if thats what youre referring to

user202729

@NewSandboxedPosts Does anybody here hate challenges just because they're short?

Pavel

<-- has a lot of simple, short challenges

Skidsdev

16:48

<-- has a mix of mostly well-received, mostly short and trivial challenges

quartata

<-- is monky

Pavel

codegolf.stackexchange.com/questions/103091/… or codegolf.stackexchange.com/questions/114219/… is my most complex challenge, I guess

Skidsdev

codegolf.stackexchange.com/questions/132387/… is probably my most complex

Stephen Leppik

So Advent of Code 2018 starts tomorrow.

Quintec

v intriguied me for a while

halite.io

5

J. Sallé

17:01

@Quintec links break without the protocol iirc

Quintec

Eek phone is hard

Zacharý

Also hat season as well.

J. Sallé

@Quintec When my boss asks me why did my productivity tank I will blame it on you.

Skidsdev

@Quintec oh no

inb4 everyone in PPCG becomes addicted to halite

Pavel

Isn't Halite salt

Skidsdev

17:03

yes

rock salt

well, also table salt

Zacharý

No

Isnt Table salt just sodium chloride?

Skidsdev

yes, so is halite

Zacharý

O_O

J. Sallé

Halite is the name given to NaCl extracted from mines as opposed to sea salt.

iirc

Skidsdev

yup, aka rock salt

ok so halite is that one ant koth we had taken to the next level basically

J. Sallé

17:07

Looks like that, yes

Skidsdev

hmm.. so you're collecting halite (rock salt), but you're in the sea, as evident by this rule: If multiple ships occupy the same location, they will collide and sink, dropping all their halite into the sea.

the gameplay overview doesn't mention language, I'm assuming JS

J. Sallé

I fervently hope it's not JS

Skidsdev

It's not

J. Sallé

Good

Skidsdev

When you go to the editor it asks what language you want, but the only option currently is Python3

I assume giving the option, even with only one option, implies they plan to support more int he future

Also because the majority of PPCG's languages are written in Python, you could in theory include the entire interpreter for said language, and use that to make the bot :P

Maybe uh.. maybe don't though. Your language will still need a way to call Halite's SDK, which is a python import

J. Sallé

17:11

@Skidsdev welp, time to go learn python >.>

Skidsdev

haha

guys... guys! there's a leaderboard

we need to flood it with ppcg-ers

wait there are multiple languages

@J.Sallé Python3, Java, C++ and JavaScript are supported

the tutorial just limits you to Python3

J. Sallé

@Skidsdev Also Clojure and Rust

Also teams.

PPCG team anyone?

Skidsdev

I can't pick Clojure or Rust

but yeah sure enough people have them listed on the leaderboard

J. Sallé

@Skidsdev They're used by leaderboard people though

user202729

@J.Sallé We need some chatrooms in that case...

Skidsdev

17:14

also Julia, JAR, Ruby, C#

yeah somebody set up a Halite PPCG chatroom

J. Sallé

Yeah there's a bunch of languages, that's cool.

user202729

:|

J. Sallé

@Quintec What have you done!? ಠ_ಠ

user202729

Well if people find it interesting I may try it later

J. Sallé

I'll jump in on it as soon as I get home today

Skidsdev

17:15

oooh

they support like 20 something languages

just the in-browser editor only supports Python3, JS, Java and C++

quartata

halite?

Skidsdev

Full list of supported languages

quartata

rock salt?

Skidsdev

Halite

yes, rock salt

and also a large-scale KotH :P

quartata

oh oh i think i remember this

Zacharý

17:17

D IS SUPPORTED!

quartata

i just saw "addicted to salt" and was confused

Skidsdev

yup!

You can also, of course, create your own library for the language of your choice

quartata

use python

Skidsdev

Okay, I made a room for halite

Zacharý

When is the challenge? When does it end?

I assume you guys are going to make like the drone from the KOTH

Skidsdev

17:21

the challenge has already started, and runs through to Jan 22nd

J. Sallé

17:32

@quartata no >:(

AdmBorkBork

@quartata You spelled "PowerShell" wrong.

New Main Posts

18:33

0

Q: Java program (multiple choice quiz bee)

Write a program that would present a multiple-choice quiz bee with a total of 15 quiz items categorized into three: easy, medium, and hard; this makes each category contain 5 quiz items. Each quiz item has 4 answer options (a – d). Pre-store the quiz details in a multidimensional array. Present o...

java

Erik the Outgolfer

@AdmBorkBork ouch... :P

quartata

@J.Sallé anything else is just gonna slow you down for this

Skidsdev

@quartata I don't seem to be having an issue in JS

also you say that, but there are a total of 3 Python users in the top 25, the highest of which is at 6

Anonymous

PHP is an option for Halite >_<

Skidsdev

oh wow it is

Pavel

18:42

Why wouldn't it be

Skidsdev

I wonder if the C++ answers do so well because they can potentially do more in the 2 seconds than other languages

J. Sallé

Because it's php

Pavel

Think about it, if we didn't have PHP, we wouldn't be able to laugh at PHP

The world would be so much worse

J. Sallé

@Pavel that's PHP's best feature by far

Skidsdev

<-- Uses PHP professionally, actually has very little complaints about PHP 7 onwards

AdmBorkBork

18:43

PHP is a programming language in the same way that a goose is a duck.

2

Pavel

...Isn't it?

<-- doesn't know avian taxonomy

J. Sallé

Geese and duck are not the same

I don't think they're even in the same Genus

Skidsdev

@AdmBorkBork by that logic, HTML is a programming language in the same way that a loaf of bread is a duck

Anonymous

> Bots have a memory limit of 1GB. If your code exceeds this limit, your bot is killed.

Anonymous

Yikes

Anonymous

18:44

There goes my idea for an Electron-based bot

Pavel

1GB is a lot

Skidsdev

@J.Sallé they're not, their lowest common relation is family (Anatidae)

J. Sallé

@Skidsdev yeah, that's what I imagined

Skidsdev

@Mego wait how would you even do that? Or were you just poking fun at Electron's gargantuan RAM usage

Anonymous

Manual memory management in C++ probably helps quite a bit, too - you can do a lot more with 1 GB if you can manage it directly

Anonymous

18:46

@Skidsdev The latter :P

Erik the Outgolfer

@Mego ...is it? status-norepro

only languages are Python 3, Java, C++ and JS

Skidsdev

@EriktheOutgolfer Yes

you don't have to use the online editor

they have libraries for 7 languages, with community contributed libraries for 10 or so more, including PHP

Anonymous

Also you can use any language you want, even if there's not a library for it, by just implementing the API

Anonymous

Jelly Halite bot when

Skidsdev

correct

from what I can tell, it does actually come down to KotH style text input and output using STDIN and STDOUT

Anonymous

18:48

Yep, it's basically a professionally-hosted KotH with libraries built for various languages

Skidsdev

yup, and it runs every year. This is its third year

looks like it's changed substantially since halite 2

in which you had to gather halite from randomized planets

J. Sallé

@Mego I was about to mention: 500 rep for the first Jelly Halite bot.

Erik the Outgolfer

ŒV ;-)

Skidsdev

Here's a post mortem of the winning bot from Halite 2

Anonymous

@J.Sallé I'll throw in another 500, but it has to reach at least silver tier for mine

Erik the Outgolfer

18:51

but... Jelly can execute arbitrary Python 3 code with ŒV

Skidsdev

@Mego I'll throw in another 1000 if it hits gold without using ŒV

Erik the Outgolfer

yes, that's a built-in

Skidsdev

50k rep to anybody who creates a bot that can win a game vs the starting bot in any of my languages

Erik the Outgolfer

...you don't have 50k rep... and that would take a lot of time to award...

in fact, if the Python code doesn't contain the Jelly string starter or any string terminators, wrapping it in “...”ŒV is enough to convert Python to Jelly

yes, newlines and all

Anonymous

Then I'll modify my bounty to forbid using eval

Skidsdev

18:56

@EriktheOutgolfer if anybody is dedicated enough to do it, I'll be dedicated enough to reward it

Erik the Outgolfer

and make sure to forbid both ŒV and v (otherwise one could simply replace ŒV with ⁾ŒVv$, possibly without the last $ too)

Skidsdev

@EriktheOutgolfer does v execute jelly code?

Erik the Outgolfer

not to mention forbid V too (yes, that alone is enough, even without ŒV and v)

yes, v is eval Jelly code with one argument

J. Sallé

@Mego yeah I want that Jelly as pure as possible! (aka actual Jelly code instead of Python code)

Skidsdev

I would argue that ⁾ŒVv$ is still using ŒV

dzaima

18:58

@EriktheOutgolfer mego said just "eval", so presumably all evals

Erik the Outgolfer

pretty sure Mego has to specify the exact built-ins so that it's objective... ;-)

Skidsdev

I dunno, we've had challenges that state "No X builtin" before, without specifying the actual builtins

Erik the Outgolfer

so, ŒV is exec Python, V is exec Jelly, v is exec Jelly with argument

AdmBorkBork

mmm, pure jelly ...

Erik the Outgolfer

@Skidsdev that is when they aren't referring to a specific language

if you're referring to one specific language, you can definitely specify exact built-ins

although... maybe not restrict V and v completely, just specify that your code, as well as code passed into the V and v built-ins, must not use the ŒV built-in (ŒV is the main culprit)

J. Sallé

19:01

@AdmBorkBork I rejoice on the fact that someone mentioned the joke

mınxomaτ

19:14

damn.dog

6

Erik the Outgolfer

...I still don't know what that thing says when I'm correct...

oh, "That's right."

Pavel

19:39

@mınxomaτ What is it? (Blocked by firewall)

Erik the Outgolfer

wikiHow image quiz

i.e. in which article, out of 4 possible choices, does this image appear?

Pavel

lol

Erik the Outgolfer

more difficult than you think

Pavel

/r/DisneyVacation

Lynn

@ETHproductions Dun dunnn! Top 10 plot twists in PPCG history.

Erik the Outgolfer

19:46

lol

Lynn

These logs are so good

Nov 12 at 21:55, by Zacharý

IT IS HARD TO FIND SOMETHING WHEN IT IS PART OF LOREM IPSUM

Dennis

What's a Halite bot?

Pavel

@Dennis halite.io is a game for AIs

You can write your AI in pretty much any language

Dennis

AI AI, CAPTAIN

Erik the Outgolfer

exactly :P

> CAPTAIN: Captain of a Halite boat.

> AI: Indicates obedience to the CAPTAIN.

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