The Nineteenth Byte

Jan Dvorak

4:00 PM

The question isn't where, but why?

TuxCopter

^

Christopher

Forgot about carrot reply userscript

Arjun

How is Minesweeper Turing Complete?

TuxCopter

@Arjun Magic (the gathering)

Christopher

@Arjun Magic the gathering is TC

Arjun

4:07 PM

Magic is real! Wow!

Leaky Nun

CMC: given a string consisting of A, B, C, or D (it can be empty), determine if the first letter is equal to the last letter.

(empty string returns true)

Arjun

@LeakyNun f=_=>_[0]==_[_.length-1]

Leaky Nun

@Arjun what the kek

>> undefined == undefined
<< true

I like this hack

Arjun

Smart me! :p

@LeakyNun Alternatively, f=_=>_[0]==_.slice(-1)

DJMcMayhem

@LeakyNun V doesn't really have booleans at all. Can I do empty string for Truthy, non-empty for falsy?

Leaky Nun

4:14 PM

@DJMcMayhem alright...

Arjun

@LeakyNun Perhaps, you can post that as a challenge (you know, for the sweet rep!)

DJMcMayhem

@LeakyNun ç^¨.©.*±$/D

Leaky Nun

3

Q: Element of string at specified index

Given a string s and a non-negative number n less than the length of s, output the character at the n-th position of s. 0-indexing and 1-indexing are allowed. For 1-indexing, n will be positive and less than or equal to the length of s. s will consist of printable characters only. Any reasonab...

+8/-5 ;_;

Arjun

+9 now

Simply Beautiful Art

-5

A: Largest Number Printable

a=Infinity;alert([a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a,a]) This assumes that this a complex number and Infinity is a number.

May we delete?

totallyhuman

4:23 PM

=_=

Arjun

@LeakyNun So, are you going to post it as a challenge?

Leaky Nun

@Arjun No, I am not

Arjun

May I?

Or someone else?

Leaky Nun

yes

it originated from @NathanMerrill though

Arjun

Oh, than they should post it!

Leaky Nun

4:26 PM

You could ask him

Arjun

@NathanMerrill Will you post it as a challenge?

Nathan Merrill

Post what?

Arjun

CMC

Nathan Merrill

Guess the function? Too broad

Leaky Nun

@NathanMerrill no

19 mins ago, by Leaky Nun

CMC: given a string consisting of A, B, C, or D (it can be empty), determine if the first letter is equal to the last letter.

Nathan Merrill

4:30 PM

None of these will be posted by me

Arjun

Can someone else post it?

Leaky Nun

@Arjun if not you, then who?

Arjun

Probably @totallyhuman, if he wants to

Sp3000

@aditsu Congrats

Arjun

Okay, I am going to post it, just a minute

Erik the Outgolfer

4:34 PM

@LeakyNun Jelly, 3 bytes: Ḣ⁼Ṫ

Leaky Nun

@EriktheOutgolfer fails for one-letter strings (because both functions modify the string)

Erik the Outgolfer

I knew it had to fail somewhere.

@LeakyNun Jelly, 5 bytes: 2Bị⁸E

(I'm sure there's a 4-byte version too)

Leaky Nun

@EriktheOutgolfer there's even a 3-byte version

but @Arjun is posting the question

aditsu

@Sp3000 for t-shirt? thanks :) I wish I won more than that :p

wonder what happened to my A large..

Leaky Nun

@aditsu glad to see you again

aditsu

4:41 PM

I suddenly lost power just when the contest started, it was really upsetting

I had so many things open too.. and some unsaved files

Sp3000

Hmm yeah, you were pretty close. C-small would have let you advance :)

Erik the Outgolfer

@LeakyNun 4-byte version: 1ị⁼Ṫ

Leaky Nun

@Arjun how is your progress?

aditsu

damn, if A large was correct, I would have advanced :(

Sp3000

If I had gotten A large I would have a T-shirt :( (was braindead, thought 1+2+3 = 4 for some reason)

Erik the Outgolfer

4:45 PM

lol what are you talking about?

totallyhuman

Erm I was mentioned..?

aditsu

hm, I made a stupid mistake

Erik the Outgolfer

@Arjun How is the question going?

aditsu

we're talking about code jam, btw there's chat.stackexchange.com/rooms/56779/code-jam-stuff

Erik the Outgolfer

oh I wasn't participating

@LeakyNun 3-byte version: [REDACTED]

aditsu

4:53 PM

@LeakyNun hai, glad to see you too

Erik the Outgolfer

wait a unicode char apparently got a couple of chars

Leaky Nun

@aditsu are you still in HK?

aditsu

@Sp3000 it looks like you didn't submit it though

totallyhuman

...ok by reading up a bit, I think I understand why I was mentioned and my answer is I'm good, if rather earn fake internet points by coming up with something myself lol

aditsu

@LeakyNun yeah

Leaky Nun

4:54 PM

@aditsu I see

Erik the Outgolfer

Arjun is still here?

Sp3000

@aditsu I never ended up doing it because I was under the impression a greedy algorithm wasn't going to work for some reason

:/

(just got told that is wrong)

aditsu

@Sp3000 how did you choose the shooters in problem C?

Sp3000

1) For each shooter, find all cells covered by | orientation and find all cells covered by - orientation 2) Brute force over all combinations of |- until you find one that covers all dots

aditsu

for A large, I think I forgot to handle the case where you have a single "2" left..

brute force?!!!

Sp3000

4:56 PM

You need a bit more than that to make it efficient enough though

Arjun

Wait, just going to post

Sp3000

(e.g. if - and | cover the same cells, pick one arbitrarily)

aditsu

I coded a greedy solution, apparently it was wrong..

there might be a graph algorithm involved

I thought brute force would be too slow for 5*50

Sp3000

Something something bipartite maybe

aditsu

oh, is this the 100th time I fail to recognize a bipartite solution?

Sp3000

4:59 PM

I dunno, just guessing since there's two options for each :P (too lazy to think)

As for brute force, if you early exit after finding a shooter that shoots any shooter no matter which of | - it is (i.e. impossible), then the case with the most shooters I saw was a checkerboard with #

But yeah tbh I didn't really expect it to be fast enough, I was just kinda hoping

aditsu

I think it's a bit trickier for bipartite since you have 2 orientations for each shooter

(except the fixed ones which you can eliminate)

Erik the Outgolfer

@Arjun Ready yet?

aditsu

oh, also each shooter shoots many cells, not just one

Sp3000

Hmm I can think of how you might formulate it as max flow, but every time I say that I'm too lazy to implement max flow/forgot how

Arjun

@EriktheOutgolfer Done.

Erik the Outgolfer

5:03 PM

Then post it?

aditsu

I have some generic algorithms pre-coded, but I think I haven't done max flow yet..

Sp3000

Yeah it's basically - given a list of pairs of cell sets, pick one set from each pair such that the union of the sets you pick is all the empty spaces

starts reading analysis

Erik the Outgolfer

@Arjun Yeah, I finally answered in Jelly!

Arjun

I hope the specs are clear!

Leaky Nun

@Arjun nice challenge.

@EriktheOutgolfer my answer was .ịE (fails for the main challenge because of the empty string)

aditsu

5:08 PM

hmm not sure how to model it even as a max flow problem.. you need 0/1 capacities for orientation choice, but large capacities for shooting cells

Arjun

@LeakyNun Thanks for the appreciation! Credit goes to you!

Erik the Outgolfer

@LeakyNun I was lucky that Ḣ returns 0 for []. ;)

Leaky Nun

@EriktheOutgolfer indeed.

Sp3000

@aditsu Hmm ignore me then, probably just being braindead :P

Erik the Outgolfer

@LeakyNun Redacting my own 3-byte version proved good.

New Main Posts

5:17 PM

4

Q: Does the start equal the end?

The Task In this challenge, your task is to write a program or function which takes in a String and outputs a truthy or falsey value based on whether the first character and the last character of the input String are equal. Input You may take input in any way you want. But, assuming the input ...

code-golf string decision-problem

totallyhuman

Huh

I thought the challenge would be easy but Python trips on the empty strings

Erik the Outgolfer

Yeah it does, that's what I'm trying too atm.

totallyhuman

I think I got it

aditsu

@totallyhuman which challenge?

totallyhuman

Yep and you beat me :P

@aditsu the one new main post's just posted

aditsu

5:26 PM

oh, I'm pretty sure mender posted it in chat last year

he came up with a cool CJam solution

oh wait, maybe it was just to extract the first and last element

Erik the Outgolfer

@aditsu {(\)\;}

simple 7 byte solution

aditsu

in an array; also, not sure why you want a block

Arjun

Thought I will gain some upvotes by posting my answer most quickly. Not even a single one, yet :p

totallyhuman

Wait erik

Doesn't yours post 0 for an empty one?

Erik the Outgolfer

Yes shouldn't it?

totallyhuman

5:32 PM

But it prints False otherwise

Erik the Outgolfer

I have asked OP about that, but both are falsey.

totallyhuman

Is there a need for consistent truthy and falsy values?

Erik the Outgolfer

OP said it's allowed.

Arjun

Erik? What happened?

totallyhuman

Ah ok

Erik the Outgolfer

5:34 PM

Also reduced to 26 bytes for me, now it has '' and False for falsey, True for truthy.

@totallyhuman Did you accidentally delete your post?

btw dupe answers are actually allowed, depends on whether you like keeping dupes or not

Arjun

Wait @EriktheOutgolfer ! I interpreted your question as Can we output any kind of truthy/falsey pair ie. 0/1, true/ false?. But seems like you were asking something else ie Does the truthy/falsey pair need to be consistent?. Well, for that the answer is "Yes". Gonna edit.

totallyhuman

Erp

Will have to change mine again

Erik the Outgolfer

@Arjun Oh... ok I'm gonna edit my answer

luckily my Jelly answer still follows the rules

totallyhuman

Your answer is still shorter lol

Erik the Outgolfer

not shorter than ~~Adnan's~~ Dennis's

totallyhuman

5:43 PM

Yeah that one....

Erik the Outgolfer

pythonception

totallyhuman

And Dennis's o0

You guys are nuts

Erik the Outgolfer

although it's probably got a typo currently (e instead of s...)

totallyhuman

That's what it relies on

To raise a name error

Arjun

Okay, I am going to sleep! Bye! Had a nice day today!

zzzzzzz....

totallyhuman

5:46 PM

Bye

Erik the Outgolfer

bye

Riley

6:06 PM

@MartinEnder Yep. Looks good.

New Main Posts

6:18 PM

-2

Q: Error in using ssl library?

Working on a RSA project and i cant access openssl library on cygwin? #include <openssl/rsa.h> #include <openssl/pem.h> #include <openssl/err.h> #include <stdio.h> #include <string.h> Then i get this compile error fatal error: openssl/pem.h: No such file or directory compilation t...

c

totallyhuman

6:29 PM

o0

There's more of these off topic ones everyday

Erik the Outgolfer

probably because "programming puzzles" could be taken to mean "programming problems"

aditsu

6:41 PM

huh, LL# -> -1

totallyhuman

Hmm could I made a challenge out of the phrase "all's well that ends well"

aditsu

should I see this as a bug or a feature? :p

totallyhuman

Why not both

Erik the Outgolfer

@aditsu feature since "" isn't contained in ""

although it's contained in [""]

aditsu

not as an element, but as a substring

Erik the Outgolfer

6:45 PM

doesn't # find for the element though?

aditsu

not with 2 arrays

Erik the Outgolfer

ooh CJam is more [messed up] than I thought...

Downgoat

@ASCII-only in cheddarshuntingyard what does:

aditsu

lol

Downgoat

            if (token instanceof CheddarShuntingYard) {
                for (let i = 0; i < token._Tokens.length; i++)
                    this.Tokens = token._Tokens[i];
                unary = false;

mean?

Erik the Outgolfer

6:49 PM

@aditsu also 1 2 3]""# is error

Downgoat

@wizzwizz4 technically not redirection :P

Leaky Nun

@aditsu where did the cheatsheet go?

aditsu

@EriktheOutgolfer yeah I noticed..

@LeakyNun I don't know, I didn't write it

Leaky Nun

Is Lynn still here?

Erik the Outgolfer

less active but yeah

aditsu

6:51 PM

I think I have a copy of it..

Erik the Outgolfer

@aditsu should always be error I guess

even on LL#

aditsu

@EriktheOutgolfer I think it should always return 0

as it does in java..

Erik the Outgolfer

I thought of it at first too

Business Cat

That probably makes the most sense

Erik the Outgolfer

but then I'd expect that L0= would return ""

aditsu

6:56 PM

nope, element is not substring

L0>"",< would return ""

Erik the Outgolfer

yeah you're right... less errors I guess

Okx

7:44 PM

Do you think I should post this yet?

New Main Posts

0

Q: Random Golf of the Day #8: Shuffle an infinite list

About the Series First off, you may treat this like any other code golf challenge, and answer it without worrying about the series at all. However, there is a leaderboard across all challenges. You can find the leaderboard along with some more information about the series in the first post. Hol...

code-golf array-manipulation random permutations

Kritixi Lithos

7:57 PM

@Riker Probably because it is very common in the Qur'an.

mınxomaτ

8:12 PM

Me: I have some free time, maybe I should clean up a few pages of code. Checks out newest commit by trainee:

Kritixi Lithos

IntelliJ?

mınxomaτ

Rider

He certainly managed to created an impressive amount of heap memory leaks in just a few hundred lines of code.

(the trainee, not Rider)

totallyhuman

8:27 PM

4

Q: Random Golf of the Day #8: Shuffle an infinite list

About the Series First off, you may treat this like any other code golf challenge, and answer it without worrying about the series at all. However, there is a leaderboard across all challenges. You can find the leaderboard along with some more information about the series in the first post. Hol...

code-golf array-manipulation random permutations

Somebody explain to me why it won't be as easy as using Python's random.shuffle

Jan Dvorak

because random.shuffle does not support infinite lists?

totallyhuman

but uh... how is it possible to input an infinite list?

Anonymous

@totallyhuman Generator, reading from a stream, reading from a pipe, etc.

totallyhuman

...yeah this challenge isn't for me yet :D

i'll try later

Anonymous

tio.run/nexus/…

Anonymous

8:35 PM

I have some ideas of how to go about it

xnor

8:49 PM

@MartinEnder Is my answer OK, or should I be taking the generator as input somehow?

Martin Ender

@xnor you mean because it's mixed I/O? I think it's fine but I'll have a closer look later

xnor

@MartinEnder No, I mean that I assume the stream g is already defined

feersum

How could that possibly be valid

Anonymous

I think that's covered under the last bullet point

Anonymous

> Alternatively, you can write a function which takes no arguments and returns one output value each time it is called. In this case, you can assume that a function has been defined which takes no arguments and returns the next input value each time it is called. You may freely choose that function's name.

Anonymous

8:52 PM

@feersum Because it was explicitly allowed in the challenge

xnor

well, my code is a program, not a function, so technically it doesn't qualify

but it would be weird if programs and function were allowed different things here

VisualMelon

Looking for feedback on: codegolf.meta.stackexchange.com/a/11910/26981

xnor

I changed it to STDIN input to be safe for now

@MartinEnder by the rules as I understand, functions being allowed to assume the generator is predefined but programs not being allowed to do so gives a weird incentive to use a function just to save on input-taking boilerplate

Downgoat

Question: how to make REPL-like behavior in java? this is not working :(

        Scanner in = new Scanner(System.in);
        while (in.hasNextLine()) {
            System.out.println("tnv> ");
            System.out.println(Main.evaluate(in.nextLine()));
        }

it only shows prompt after you submit

Phoenix

That's because in.hasNextLine() waits until there is actually a line.

Anonymous

9:04 PM

@Downgoat System.out.flush()

feersum

ninja'd

Downgoat

actually looks like I needed a do..while :P

Anonymous

Oh right, that would do it too

Phoenix

Or just do true and catch the exception.

Downgoat

oh hello there nullpointerexception

feersum

9:05 PM

Do-while seems wrong to me.

The input may have no lines.

Downgoat

@feersum yeah, .nextLine() is giving null sometimes now

Phoenix

You don't even need to try catching the exception.

Anonymous

Doesn't Java have a way to read a line from STDIN with a prompt?

Phoenix

@Mego Sys...println("prompt");Scanner.nextLine();

Not built in, no.

Also, @Downgoat you might want print and not println so the input appears on the same line after the prompt.

Downgoat

@Phoenix while(true) loop it is

@Phoenix yeah :P just realized

feersum

9:07 PM

Oh, I suggested flush assuming you were doing print and not println...

Phoenix

If the user passes EOF to a REPL, they should not be surprised that some kind of error occurs, anyway.

feersum

No, they should not expect an error, they should expect it to exit.

Phoenix

Or you could catch(NoSuchElementException e){System.exit(0);}

Jan Dvorak

I would expect it to reprompt

Downgoat

@JanDvorak oh no, that's what node.js does and i hate it for that

Phoenix

9:10 PM

If you <C-d> into a terminal, it will exit the terminal.

Jan Dvorak

I really don't want the repl to bail out because I copy-pasted an empty line to it, especially if it means the rest of my clipboard goes to the OS console...

Downgoat

Question: how to do BigDecimal.pow(BigDecimal)

feersum

Um, how is an empty line an EOF

Phoenix

"" != EOF

Anonymous

Besides, an empty line is "\n"

Jan Dvorak

9:14 PM

Evil idea of the day: make a >= b an alias for a = a > b

17

Downgoat

@JanDvorak gimme a sec

feersum

And don't forget a == b -> a = a = b as well.

Anonymous

@feersum Kinda surprised PHP doesn't do that

betseg

plz make a === b -> a = a == b, not a == b -> a = a = b plz

totallyhuman

o0 you guys are sorcerors

DJMcMayhem

9:19 PM

@JanDvorak D:

Downgoat

@JanDvorak for JS: astexplorer.net/#/gist/4f9040ad6ce97cc68c28d39587f63458/…

totallyhuman

eeevil sorcerers

Downgoat

@ASCII-only on scale of 1-10, how important is having VSL REPL?

Phoenix

Not very IMO

Nice to have, but priorities

Downgoat

it's not that. VSL is compiler however though so scoping is kinda not so simple to share over a REPL

what I could do is copy the entire execution context every line

but that would be slow

New Sandboxed Posts

9:37 PM

0

A: Sandbox for Proposed Challenges

Plane Blow-up mathpolynomialgeometryalgebra Blow-ups are powerfull tools in algebraic geometry. They allow to remove singularities from algebraic sets while preserving the rest of their structure. If you're not familiar with any of that don't worry: In the following we are considering the blow-...

Downgoat

Question: how to check if tty in java?

TuxCopter

Make a JFrame and check if it errors?

Anonymous

@Downgoat Check if System.console() != null

Downgoat

wtf, java says to disable echo you should backspace faster than user can type...

Anonymous

Alternatively you can use JNI to call isatty

Anonymous

9:41 PM

@Downgoat System.console().readPassword()

Downgoat

I think I am reading very old java docs :/

@Mego thanks, this works :D

Anonymous

@Downgoat Probably, java.io.Console was added in JDK 6

Anonymous

@Downgoat Glad to help

Phoenix

@Mego If you just search "Java doc <class>", it will point you to the Java 7 docs.

Anonymous

@Phoenix I'm not the one reading outdated docs :P

Phoenix

9:48 PM

Yeah, I just wanted to point that out. Kinda weird.

Downgoat

Question: is there a way to have arrow keys (e.g. left, right) work when I do .readLine?

I am trying scanner and Console object

Okx

What do you mean?

Downgoat

like right now if I do .readLine and click arrow key I get ^[[C

Okx

I don't get it

Downgoat

Well instead if should move the cursor left

I could write my own thing with raw mode and stuff but seems like Java should have built-in

New Main Posts

10:03 PM

0

Q: 11 = (1+2+3+4+5) - (1+2+3) + (6) - (4)

Given a positive integer N, your task is to return the number of steps required by the following algorithm to reach N: Find the smallest triangular number Ti such that Ti ≥ N. Build the corresponding list L = [ 1, 2, ..., i ]. While the sum of the terms of L is greater than N, remove the first ...

code-golf math

Anonymous

@Downgoat Not builtin, but jline.sourceforge.net

Christopher

Watch this (not rick roll)

It gets really deep at the end

Okx

this > that

Christopher

@Okx My video shot me in the feels at the end

feersum

@MartinEnder Would a program that takes two number j, k (from 0-19) as a seed, prints out the first j items unchanged, and after that reads in batches of 20, prints the last k items of the batch, and then prints the first 20-k be a valid answer? If not, why?

Conor O'Brien

10:15 PM

@MartinEnder I was wondering about your challenge--my method is to store an array of 9 characters, read characters to fill the array, then randomly output and replace indices in this array. I think this is sort of how the python answer works, and I was wondering if it's a valid approach.

betseg

@Okx thats beautiful

Conor O'Brien

haha ping double team. Out of curiosity, are you writing a C answer @feersum?

Okx

@betseg you better star it then :P jk

feersum

No.

betseg

i posted it before you, ninja'd you, you star me :P

quartata

10:18 PM

@Riker Now I know why it doesn't work: I put in the method that gets called on the first bite of corpses

not regular food

Phoenix

What is context?

quartata

Context is from almost a year ago

something I did not realize until I replied to the message

Oct 8 '16 at 1:04, by quartata

#ifdef QNETHACK
    } else if (otmp->otyp == PROTEIN_SUPPLEMENT || otmp->otyp == VEGGY_SUPPLEMENT || otmp->otyp == STARCH_SUPPLEMENT) {
      pline("This makes you feel disguistingly healthy.");
#endif

oh and I typo'd disgustingly apparently

past self was a little dumb

10

Anonymous

@quartata Such is life

quartata

It's kind of funny to go back to this code after a while and remember all the little quirks I learned about nethack along the way

Phoenix

Nethack is that videogame you lot play, right?

Anonymous

10:31 PM

@Phoenix No that's code golf