The Nineteenth Byte

flawr

06:33

@JohnDvorak odd = prime confirmed:)

New Sandboxed Posts

09:41

0

A: Sandbox for Proposed Challenges

Do the 26 richest billionaires own as much wealth as the poorest 3.8 billion people? code-golfnumberinteger Introduction: I just read this post with the same title when I came across it in the HNQ. In this question it is being discussed if the claim of president-candidate Bernie Sanders, who c...

New Sandboxed Posts

12:44

0

A: Sandbox for Proposed Challenges

H interpreter H is a relatively simple language that does not implement advanced features. Create an interpreter for H. The winning criterion for this challenge is code-challenge. Here is everything in the H command reference just for reference purposes: Def The def command is used to define...

New Sandboxed Posts

15:47

0

A: Sandbox for Proposed Challenges

Enable 2-char Jsfuck Provide a shortest code that makes JavaScript able to do everything JavaScript is supposed to do, with only [ and ]. You can choose your environment(FF/node/etc). Answering in 6-char JsFuck or something similar is welcomed.

ThePlasmaRailgun

17:29

I recently discovered toolz, a Python library for functional programming, and I have fallen in love with it

github.com/pytoolz/toolz

Oliver

17:51

Any mod feel like updating the site name mentioned here?

Adám

18:07

@Mego @DJMcMayhem @Dennis ^

DJMcMayhem

Should I say "Code Golf & Coding Challenges", or just "Code Golf"? I prefer the second

Oliver

I like Code Golf

Erik the Outgolfer

> Code Golf

but be sure to put it in italics

oh, and there's one at the bottom too!

DJMcMayhem

status-completed

Erik the Outgolfer

btw, the italics are important in that page because PPCG might be somebody's first interaction with SE, but they might already know what "code golf" means, and then they could be like "um... wut" otherwise

Veskah

18:15

Needs to be in 72 pt. Impact Bold

Gotta be subtle, ya know?

Erik the Outgolfer

btw, it might be time to get this off the Featured list

DJMcMayhem

I like S͟U͟B͟T͟L͟E͟T͟Y͟ too

Erik the Outgolfer

inb4 "w?h?a?t? ?a?r?e? ?y?o?u? ?s?a?y?i?n?g? ?t?h?e?r?e???" :D

Oliver

If anyone wants a better visual of the new header, you can go here: https://cdn.sstatic.net/Sites/codegolfmeta/img/header-background-image.svg?v=7b61cc011d06

and run:
var allElements = document.getElementsByTagName("*");
for(var i = 0; i < allElements.length; i++) {
var element = allElements[i];

if(element.getAttribute("fill")) {
element.setAttribute("fill", "black");
}
}

2

AdmBorkBork

@DJMcMayhem Subtle. Like the b.

New Sandboxed Posts

18:29

0

A: Sandbox for Proposed Challenges

Implement ave This is one part of a multi-part series inspired by various built-ins in R. Credit goes to digEmAll for suggesting this one. ave calculates particular grouped values of a list. For example, we would group x in the following way based on the criteria given in f: x = [2, 1, 3, 5...

DJMcMayhem

It's funny, the word "subtle" looks correct to me, but no matter how many times I double check the word "subtlety", it looks like it's spelled wrong to me.

Veskah

Subtle Tea

Rick

18:52

If I have a directed graph generated from permutations and it is generated as integers from 1 to "n". I have the original sequence and I need to check if that sequence can be constructed from the graph. for example lets say the permutation sequence is [4,1,5,2,6,3] and our adjacency matrix for our graph is {1:[5],2:[6],5:[2],4:[1],6:[3]} Would the Hamiltonian path in the graph be considered the original order of the sequence assuming we have the correct starting vertex?

ThePlasmaRailgun

If I understand what you're saying, then yes

I'm kind of confused about your specification for the adjacency matrix though

Rick

thank you!! I thought I might have been losing my mind there for a second

ThePlasmaRailgun

I think it would be easier to understand if you put it in order, like {4:1, 1:5, 5:2, 2:6, 6:3}

Rick

@ThePlasmaRailgun well it's a directed graph the sequences are like this [[5,2,6,3],[4,1,5,2]] but I interperate it as this {1:[5],2:[6],5:[2],4:[1],6:[3]}

ThePlasmaRailgun

Yes, but that's the exact same adjacency matrix, just slightly shuffled so it's easier to just look through and verify it follows a hamiltonian path equivalent to your permutation

Rick

18:59

@ThePlasmaRailgun good point that would have made it a lot easier

@ThePlasmaRailgun are there any nice theorems for a Hamilton path

ThePlasmaRailgun

Also, you might want to look at Rook generators, which are polynomials generating the number of possible matrices where every nonzero value is a 1, and every row and column contains only a single 1, no more, no less.

That ends up being a problem of how many possible permutations there are

Ignoring rotations and mirrorings

Which is an interesting little twist that can end up being useful

Rick

nice! will do that

ThePlasmaRailgun

If you're interested specifically in permutations where no element stays in it's original place, that's called a derangement problem, and there is also a formula for it, it ends up being equivalent to a similar "rook problem" where placing 1s in the diagonal is forbidden

Rick

derangement problem is this mostly used in encryption or decryption

ThePlasmaRailgun

It's used in a lot of things

IDK about encryption, I don't think it's in any major algorithms

Anytime when you want to reorder something so that the elements are not in original order, that's derangement

Rick

19:08

sorry what I really meant what kind of problems is it mostly used toward solving

ThePlasmaRailgun

Oh

Here's wikipedia's example: Suppose that a professor gave a test to 4 students – A, B, C, and D – and wants to let them grade each other's tests. Of course, no student should grade his or her own test. How many ways could the professor hand the tests back to the students for grading, such that no student received his or her own test back?

It really ends up being used almost anywhere permutations are used, because it's just a slightly restricted permutation

Rick

interesting so distribution at scale

ThePlasmaRailgun

Random permutations are used pretty often in interleaving and deinterleaving, which are methods to make signals more robust

Interleaving is frequently used in digital communication and storage systems to improve the performance of forward error correcting codes. Many communication
channels are not memoryless: errors typically occur in bursts rather than independently. If the number of errors within a code word exceeds the error-correcting code's capability, it fails to recover the original code word. Interleaving ameliorates this problem by shuffling source symbols across several code words, thereby creating a more uniform distribution of errors.[12] Therefore, interleaving is widely used for burst error-correct…

Rick

@ThePlasmaRailgun thanks a lot that really did help! :)

ThePlasmaRailgun

No problem!

New Main Posts

19:29

0

Q: Write an interpreter for H

H is a text-based, weakly-typed language. Create an interpreter for H. The winning criterion for this challenge is described in popularity-contest. Here is everything in the H command reference; the command reference of H is very hard to navigate through, and some parts are missing. Please do ...

New Sandboxed Posts

20:11

0

A: Sandbox for Proposed Challenges

Find the closest hex color shorthand In CSS, colors can be specified by a "hex triplet" - a three byte (six digit) hexadecimal number where each byte represents the red, green, or blue components of the color. For instance, #FF0000 is completely red, and is equivalent to rgb(255, 0, 0). Colors ...

MilkyWay90

@EriktheOutgolfer Yeah, I remember seeing that too and thinking the exact same thing

And should this still be pinned?

Erik the Outgolfer

it will be unpinned in a short while, 14 days have almost passed

MilkyWay90

Oh, okay

Adám

Give it 6-8 weeks.

MilkyWay90

6-8 weeks

Why is 6-8 weeks the default time for anything on SE

Adám

20:21

587

A: The Many Memes of Meta

Meme: 6 to 8 Weeks Originator: Jeff Atwood First Heard: May 13th, 2008 Cultural Height: In about 6 to 8 weeks Definition: The time estimate given "off the top of my head" when the Stack Overflow team has only a vague idea of how long a task will take because they have little-to-no formal sche...

MilkyWay90

Oh

There should be a challenge for parsing HTML

Adám

@MilkyWay90 Using regex?

MilkyWay90

Then somebody would submit a regex answer

@Adám Yes

Adám

@MilkyWay90 He comes.

MilkyWay90

Then bobince would join PPCG

Tony the Pony He Comes

That should be a horror movie name

"We've just got to parse this webpage for hidden contents!"

makes regex

"What is that in the distance?"

"A-a pony?"

Zalgo covers his screen

"Tony the Pony!"

Adám

20:24

@MilkyWay90 Btw, that should be closed as unclear. Define HTML!

MilkyWay90

@Adám pastes entire HTML specification

Adám

@MilkyWay90 Which one?

MilkyWay90

@Adám yes

Adám

:-)

MilkyWay90

But yeah, It would exceed SE's 30000 char limit

My inbox is getting littered with my SO meta posts

Adám

20:26

@MilkyWay90 Not to mention, it'd fail on a lot of web pages. E.g. xyz

MilkyWay90

@Adám Or no trailing tags

Erik the Outgolfer

@MilkyWay90 *65536 :D

MilkyWay90

<iiiiiiiiiiiiiiiii>

Adám

@MilkyWay90 An actually viable target would be X(HT)ML.

MilkyWay90

@EriktheOutgolfer It's been upgraded?

Erik the Outgolfer

20:27

what? that's just PPCG's custom char limit for posts

MilkyWay90

@Adám Okay

@EriktheOutgolfer Oh, I thought it was the same for all SE posts

Erik the Outgolfer

in fact, meta still has the 30000-char limit

MilkyWay90

There we go, finally fixed all the typos after 4 attempts

@EriktheOutgolfer That was a typo, I meant SE

We should probably make a meta post explaining what PPCG is now that our official abbreviation is CGCC

Because a lot of people (including me) will keep on using PPCG

Erik the Outgolfer

or we can edit Adám's

MilkyWay90

@EriktheOutgolfer Adám already made one?

Erik the Outgolfer

20:31

long ago

MilkyWay90

Oh yeah I remember seeing that

It was an answer for explaining all of the PPCG terms

Adám

32

Q: What are the PPCG specific abbreviations and terms?

Newcomers to PPCG are often compelled to ask what many of our abbreviations and terms mean. Let us list them here so this information always will be easily available.

discussion chat new-users faq-proposed

MilkyWay90

@EriktheOutgolfer Okay, edited it

Erik the Outgolfer

> CGCC: Programming Puzzles & Code Golf

Adám

@MilkyWay90 It was already on the list, but I've updated it now.

MilkyWay90

20:35

Oh whoops

Adám

@MilkyWay90 I'll fix it.

MilkyWay90

Thanks

Erik the Outgolfer

@Adám MilkyWay90 added the CGCC abbreviation which wasn't already there though... I'll add that in

oh lol ninja

Adám

@EriktheOutgolfer It was added wrong, btw.

Erik the Outgolfer

@Adám yeah, the part I quoted above :D

MilkyWay90

20:38

The SE glossary is amazing

Adám

@EriktheOutgolfer Oh. I see that now.

MilkyWay90

The people who contributed had a lot of commitment

And they have reprex there too

Erik the Outgolfer

you mean SO?

imo, "reprex" isn't as good as the good old "MCVE"

> but... my question doesn't have to go with reg... oh, rePRex... wut

MilkyWay90

For the glossary

I thought reprex isn't in use

Because it's the most downvoted question in SO Meta

Erik the Outgolfer

it's been forcefully established, that's why

MilkyWay90

20:41

-321

Q: Min-Reprex: a less awkward name for MCVE

Update: ok, ok, this was a wee bit premature - here's the follow-up proposal: MCVExit redux: I don't need a milkshake to know when I've missed the mark Five years ago, we set out to write up some guidelines for folks asking debugging questions on Stack Overflow. Andrew Thompson, auth...

discussion help-center mcve terminology

Oh that's min-reprex

But I remember reprex being disliked too

@EriktheOutgolfer It seems to be redirecting [mcve], [reprex], etc all to the same help page

So I don't think it's been forceful

Erik the Outgolfer

it's still the "official" term, although I'd still use "MCVE" over "reprex", the latter is confusing and looks a lot like "regex"

Poke

> The full title is long, and the initialism is... Also long

> reprex

hmm

the heck kind of argument is that

reprex is longer than mvce

MilkyWay90

@Poke I think they are counting in syllables

Erik the Outgolfer

also, "MCVE" can be a mnemonic, while "reprex" is more like just the "VE" part

MilkyWay90

Agreed

Reprex sounds too much like "regex" for me to recognize it as minimal reproducible example quickly

Erik the Outgolfer

20:49

in fact, "MCVE" says more than either "reprex" or "MWE"

MilkyWay90

yeah

I like how April Fools meta posts are always closed as "problem cannot be reproduced"

Erik the Outgolfer

otherwise the close reason would be shoved in the comments

J. Sallé

21:32

Had a project on production since late 2017. Yesterday, client tried to update some stuff on their server and moved a bunch of folders around, even the ones they've been specifically told to leave alone; project broke. Rolled everything back, project is still broken. Now I don't know whether I'd rather shoot myself or the client.

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