The Nineteenth Byte

vzn

12:23 AM

0

Q: recording highlights of codegolf site history

this site is not very old and yet, speaking as mostly an "outsider," clearly has a colorful/ unusual history. it is not a typical site for stackexchange and has many unique aspects, such as demographics like a very dedicated user base, young, and very eager to learn, etc. my suggestion is that s...

discussion

New Meta Posts

12:36 AM

1

Q: recording highlights of codegolf site history

this site is not very old and yet, speaking as mostly an "outsider," clearly has a colorful/ unusual history. it is not a typical site for stackexchange and has many unique aspects, such as demographics like a very dedicated user base, young, and very eager to learn, etc. my suggestion is that s...

discussion

trichoplax

8:15 AM

Is the next Fortnightly Challenge decided purely based on most votes? Or is there discussion of which one is most ready?

Martin Büttner

8:51 AM

@trichoplax the idea is to base it purely on votes. I don't think there is any concept of "ready" for the themes suggested there.

trichoplax

So it looks like Data Structures unless there happen to be any last minute votes. When is the cut off?

Martin Büttner

there's no hard cutoff, but the date for picking it is tomorrow

hm, I wonder why people are opposed to that meta question. an answer from one of the downvoters would be nice

@trichoplax re your comment, I guess it depends on what you consider young :P

trichoplax

@MartinBüttner yes lol. I upvoted though - it would be a great post to have, especially for people joining the site. It can give an insight into why there are questions from years ago that would no longer be accepted.

Lembik

data structures!

trichoplax

@Lembik It's in the lead by 3 votes at the moment...

Lembik

9:05 AM

@trichoplax codegolf.se is so grown up these days :)

soon you will require a PhD certificate to log in :)

trichoplax

lol

Lembik

I have to say.. choosing the right data structure problem is non trivial

dimacs11.cs.princeton.edu/competition.html is not to do with data structures but looks like the direction part of codegolf is going in

trichoplax

At least with a fortnight we have more time for throwing around several different ideas in the chat room before deciding

Martin Büttner

@Lembik I'm sure that's why Sp3000 submitted it for the fortnightly challenge instead of just going ahead and posting it himself ;)

Lembik

not number 11 specifically.. just the general model

dimacs competitions + kaggle :)

if I give you a list of file names, can anyone think of a neat way to check that the files in the current directory are a subset of those?

I mean clearly I could write a python script that made a set of the file names of interest and just looked up each one in the directory in that set

but I meant something more compressed and neat :)

trichoplax

9:14 AM

Compressed in terms of expressing it in code, or in terms of what it does in the background?

Lembik

in terms of expressing it in code

I have a weakness for obscure bash tricks, for example :)

trichoplax

is it a one liner in python?

Lembik

oh.. umm

I don't know if that can be done

trichoplax

I'm not that familiar with file system manipulation

Maybe you should post it as a question :)

Just posting in the sandbox might give you a very short solution that would show that it isn't suitable as a main site question - but then you'd have your answer anyway...

Lembik

good idea :)

grc

9:39 AM

@Lembik something like set(file_names) >= set(os.listdir('.')) ?

Lembik

9:56 AM

@grc oh that's surprising!

talk about overloading :)

does os.listdir list directories too?

Lembik

10:15 AM

maybe I should have asked a simpler question for my first fastest-algorithm question ...

grc

@Lembik yeah - use os.walk if you need to separate files from directories

Lembik

@grc interesting! Python has everything

grc

import antigravity

Lembik

yes I know about that :)

grc

:P

Sp3000

11:39 AM

@MartinBüttner Basically, that is the reason :P Also I was hoping someone would know some more interesting structures

Suffix tree's about the only cool thing I know

overactor

12:31 PM

I've done some rudimentary analysis of the keep your distance challenge

It seems like if (a+b+c+d)^2-4(a^2+b^2+c^2+d^2)<0 we'll find a local score minimum at (a+b+c+d)/4 and so either 1 or 99 was the winning choice

Lembik

@so

@Sp3000 I know data structures if that helps

overactor

otherwise, we'll find a local maximum at (a+b+c+d)/4 and two local minima at sqrt((a+b+c+d)^2-4(a^2+b^2+c^2+d^2)) distance on both sides of it

Sp3000

That's what the chat is for :D everyone can throw in ideas

overactor

so in that case 1, 999 or (a+b+c+d)/4 has the highest score

Sp3000

(so yes, it does help)

Lembik

12:35 PM

@Sp3000 van Emde Boas trees would be a cool and quite advanced challenge

where we have to time inserts, deletes and predecessor queries... somehow

Sp3000

@overactor What's a,b,c,d?

overactor

@Sp3000 The four numbers that were picked in a round

Sp3000

Oh, starting with a simpler case?

Lembik

@Sp3000 the main problems would be a) how to specify the input b) how to time the results

@Sp3000 another alternative is not to define the data structure but rather to define the abstract data type

@Sp3000 this has very nice advantages and also maybe some disadvantages :)

the competition could be about space and time if we could agree on ways of measuring them

Sp3000

Space is probably going to be more of an issue

Lembik

12:40 PM

@Sp3000 as in more difficult to measure?

Sp3000

Time at least is okay for most languages if you use a common system (or three)

Lembik

@Sp3000 I think it's easy enough to measure the total RAM used by a process

but this of course is bad for some languages

Sp3000

Yeah, like I'm not sure whether some languages might implicitly use more memory

Lembik

@Sp3000 or we could say the whole thing has to be represented in an array of integers in some range

and just count the length of that array

this makes coding it slightly more tricky

I suppose almost all languages have an array of integers

Sp3000

Most I think do, or something array-like at least

Lembik

12:58 PM

what do you think of the abstract data type versus data structure question?

Sp3000

Hmm I'm not sure I know what the difference is, unfortunately

Lembik

oh well let me tell you :)

Sp3000

sits down and listens

Lembik

"An abstract data type is defined only by the operations that may be performed on it and by mathematical pre-conditions and constraints on the effects (and possibly cost) of those operations. "

so in an abstract data type you don't say HOW anything will be done

just what operations have to be supported

for example, insert(x), delete(x), find next biggest number bigger than x

in a data structure you say how this should be done

so an abstract data type challenge would let the programmer choose how to solve the problem

Sp3000

Oh, I see

Lembik

1:01 PM

that is which data structure to use

Sp3000

So like for heaps you don't say "So this is how we fix the heap after an insert..."

Lembik

a binary heap is a data structure. A priority queue is an abstract data type

priority queues support various operations (insert, remove minimum, read minimum i think)

you could implement that in a number of ways, one efficient way is a binary heap

Sp3000

Ah, that makes sense

Lembik

great :)

Sp3000

Abstract data type sounds more fun if you put it that way, since you need to think about the implementation

Lembik

1:04 PM

yes!

the problem we will have is choosing test cases that force people to have interesting solutions

the risk is that our test cases are really fast with some dumb solution

they ideally need to be in a sandbox for people to play with

Sp3000

Fortnightly sounds like it was a great idea now

Hmm the square root thing on keep your distance makes things pretty skewed...

It's not just in the middle of the largest gap - in fact, it seems very far from it usually

overactor

1:31 PM

@Sp3000 It's usually either 1 or 999

Sp3000

Damn :/

overactor

the case where you said it's 556, it's actually 1

999 is also better than 556

Sp3000

Is it not 200?

overactor

the worst possible choice there is 547.5 I Think

@Sp3000 I meant the one that already includes the 200

Sp3000

It's (556-1)**.5 + (556-200)**.5 + (990-556)**.5 + (999-556)**.5, right? Or have I misunderstood the scoring still?

overactor

1:37 PM

I think I'm being silly

I was squaring the distances for some reason

And then taking the square root of everything

Sp3000

Well that's a bit hard to fault, Euclidean's common :)

overactor

(a-b)^2 was so set in mind mind in association with distance

Rainbolt

3:19 PM

One of my coworkers told me that a Visual Studio extension existed that could recursively reload all dependencies for a given project. Now he has no recollection that he ever told me that. Does anyone here know what extension he might have been talking about?

nyuszika7h

3:51 PM

cv-pls codegolf.stackexchange.com/q/44810/344

Nathan Merrill

...there's a Community edit that literally does nothing

codegolf.stackexchange.com/posts/44786/revisions

it doesn't seem like a ping because its on a relatively recent question with lots of answers (Lab Rat Race)

nyuszika7h

@NathanMerrill "literally does nothing"? It adds syntax highlighting, like the edit summary says.

feersum

It's an anonymous edit

Nathan Merrill

the text is the same

why would that change the highlighting?

I thought stackexchange used markdown

or some version of it

nyuszika7h

@NathanMerrill Have you even bothered to check the Markdown source diff?

Nathan Merrill

4:04 PM

oh, I thought that automatically showed

thanks :P

feersum

It does automatically show

<!-- language-all: lang-java -->

Nathan Merrill

I have to click on "side by side Markdown"

I thought that it showed the markdown when initially looking at the edit

nyuszika7h

@NathanMerrill It does for me.

Nathan Merrill

ah ok

Rainbolt

Maybe it remembers your last choice and shows that?

Optimizer

4:25 PM

I created a 107 byte solution for the new rubiks cube challenge, but realized it was not completely correct :(

Martin Büttner

5:52 PM

Markdown question: how do I write C# (and nothing else) into a level-3 header?

Geobits

Use html instead of Markdown ;) <h3>C#</h3>

Martin Büttner

oh yeah, I keep forgetting that works

Martin Büttner

6:51 PM

:/ I wanted to do some crazy ODE solving for the 100-snippet, but the double pendulum equations are just way too long.

New Sandboxed Posts

8:23 PM

0

A: Sandbox for Proposed Challenges

Calculate cellphone key presses as quickly as possible from a cellphone keyboard! Here's a nice challenge: Calculate cell-phone keypresses. It has you calculate the amount of keypresses it takes to produce a set of characters on a cellphone keyboard. That challenge was ordinary code-golf. This ...

feersum

8:33 PM

another phone keyboard challenge? wtf...

Martin Büttner

@feersum I commented something to that effect. I don't mind having further phone keyboard challenges, but at least the actual challenge should be novel.

Lembik

8:50 PM

well I got an answer... with an hilarious score :)

(100^100)*100 !

(not factorial)

Martin Büttner

this is pretty cool: play.elevatorsaga.com

Rainbolt

9:48 PM

Is it better to delete/fix/undelete or just fix in place if you realize you really screwed up a code golf, assuming you are working on it now and it won't take very long?

Martin Büttner

you golfed something :o

Rainbolt

I royally screwed up something for sure

Martin Büttner

@Rainbolt if I know I can fix it within a minute or two, I'll just fix it. if it takes longer than that, I'll delete/undelete

I'm sure you can shorten that a lot if you expect the input as a list and do .sum() instead of .count('1')

Rainbolt

Ok, with that I will delete and reopen later

Seems as though I have a lot of work to do

Martin Büttner

"delete and reopen" makes feel about as uneasy as "[foobar)"

Doorknob

9:53 PM

Rainbolt

delete and undelete?

Martin Büttner

nice, I just added a clearer explanation to my answer and got a downvote for it :D

dem cjam haters

Rainbolt

How to dismiss annoying mismatched tags: store it in a string
string myString = @"<div>Q: How do you annoy a web developer?</span>";

If ReSharper doesn't care then I don't care

Doorknob

@? Is that... Objective-C?

Rainbolt

@MartinBüttner linky?

Martin Büttner

9:58 PM

@Rainbolt same question

Rainbolt

@Doorknob @MartinBüttner The @ symbol in C# means verbatim string literal.

Martin Büttner

I know

by "same question", I meant "my answer on the same question"

Rainbolt

Oh... haha that was confusing

Martin Büttner

(in response to your request for a link)

Doorknob

You can look at Programming Puzzles & Code Gold for inspiration. — dmckee Mar 21 '11 at 1:30

Code gold!

3

Rainbolt

10:02 PM

@Doorknob Are you stalking dmckee or are you Googling how to improve your game?

ArtOfCode

Could someone edit my Sandbox post into the directory?

Martin Büttner

sure

Doorknob

@Rainbolt No, I found it via this meta post. :P

Martin Büttner

@ArtOfCode done

@ArtOfCode what's with the language restriction?

oh, just saw the sandbox notes

Sp3000

@MartinBüttner Congrats on 100

Martin Büttner

10:06 PM

@Sp3000 thanks :)

I've been trying to come up with a good corresponding snippet, but the nice ideas I had are too long

Sp3000

Ahaha k :)

New Sandboxed Posts

0

A: Sandbox for Proposed Challenges

Transposing for C# (not the language) code-golf c# java python In this challenge, your job is to transpose a series of notes which you will be given so that the resulting sequence contains as many C# notes as possible. Input You may write a function or program which accepts one argument: an a...

Martin Büttner

@ArtOfCode I don't think the time restriction is really necessary at all. Something like "must run within 10 seconds on a reasonable desktop PC" seems absolutely sufficient.

you should definitely include more background about the challenge though. don't assume people know what "transposing" means. and I'd prefer if the list of frequencies was included in the challenge.

Rainbolt

Oh neat. Python array slicing handles out of bounds. So I can do this:
list = [1,2,3,4] # a list with four elements
slice = list[3:7] # a slice from the fourth to the eighth element

Sp3000

I think it'd be good if you mentioned that the frequencies are related by a ratio of 2^1/12 btw

Rainbolt

10:10 PM

Must.... refrain... from posting tip kdjfhSALDf

Doorknob

@Rainbolt That only outputs [4] for me. :(

Sp3000

Otherwise the frequencies look somewhat random

And that A4 being 440 is the base point

Rainbolt

@Doorknob That's the point. It doesn't give you an array out of bounds.

It just slices what it can, and ignores the fact that you suck at counting.

Doorknob

Oh, I was expecting [4, 1, 2, 3, 4].

Rainbolt

You were expecting the end of the array to wrap back around to the front of the array?

Nathan Merrill

10:17 PM

@MartinBüttner I'm working on that elevator site

Martin Büttner

it's pretty fun, isn't it?

Nathan Merrill

but I don't know javascript well enough

all it does is sit there and freeze

I think I caused an infinite loop (as not even people appear)

but, yes. It is fun

do you see the bug?

{
    init: function(elevators, floors) {

        for (var i = 0; i < elevators.length; i++){
            elevator = elevators[i];
            elevator.destination = i;
            elevator.dest = [];
            for (var j = 0; j < floors.length; j++){
                elevator.dest[j] = false;
            }
            elevator.on("floor_button_pressed", function(floorNum) {
                elevator.dest[floorNum] = true;
            });
            elevator.on("idle", function() {
                max_distance = 0;

I've checked all the braces, and they are right

I've verified that it gets past the initial for loop

which means that it is freezing on an event

but it seems that no event ever gets called

Martin Büttner

have you checked the console?

if no people appear there's usually an error

this isn't going to work though, because in all those functions elevator will ultimately have the last value you gave it in init.

I did something like this to make all elevators work the same:

elevators.forEach(function(elevator) {
    elevator.on('idle', function() {
        // do something with `elevator`
    }
}

this way, each elevator is actually in its own closure

Nathan Merrill

closures XP

Doorknob

Is that like Windows XP, only written in JS?

Optimizer

10:33 PM

@MartinBüttner I suppose you have seen alexnisnevich.github.io/untrusted ?

Martin Büttner

heh, looks fun

Rainbolt

I'm having an awful lot of trouble getting the index of the max in Python

max returns the maximum value rather than the maximum index

enumerate looks like it returns both a value and an index, but I can't figure out the syntax for calling max on it

I've managed this much:
def a(b,c):
    for d,e in enumerate(b):
         print d,sum(b[d:d+c])

It prints a list of the indexes and their sums, but I only want to print the one with the highest sum

Doorknob

@Rainbolt maxsum = max(map(sum, b))

Use index if you need the index, too

Sp3000

You can do what feersum did, which is use the key parameter of max

Alternatively, you can sort the (index, sum) pairs and take the last one

(Although for that to work they'd need to be (sum, index) pairs)

Rainbolt

Ah, feersum beat me to the punch

At least I learned how to do it :)

Sp3000

10:48 PM

:) Learning! plays a fanfare

Rainbolt

Thanks for that. Now in my head Dora the Explorer keeps exclaiming "Learning!" followed by fanfare.

I am not excited about this weather :(

Is there a way to onebox chat messages and also include a caption? Instead of double posting?

Doorknob

@Rainbolt No. Well, you can post an image with hover text, but that doesn't really count.

lorempizza.com/img/1.jpg "like so"

... err, whoops, maybe not. Forgot the syntax. But something like that.

Rainbolt

@Doorknob Can you edit? I am taking a screenshot for a feature request on meta and I want to make it purty.
I am not excited about this :(
I am not excited about this weather :(

Thanks

Nathan Merrill

11:05 PM

@MartinBüttner I'm running into buggy situations with that game

where I will start the game, and none (or just one of my elevators move)

but if I restart the game, everything runs just fine

Martin Büttner

hm, no clue

trichoplax

Do you need the http:// ?

Rainbolt

Apparently

trichoplax

ignore me lol

you corrected it as I pressed enter

In Firefox when I copy the address bar (that doesn't show http://) it includes the http:// in the clipboard so when I paste the whole address shows up

Sp3000

11:22 PM

:( trying to run the Keep your distance controller but I don't know how to Java - has anyone else tried?

Rainbolt

I mentioned us meta.stackexchange.com/q/247470/254466

And I subtly complained about the cold rainy weather

Quick! Fill up the chat with smart things so that we look good!

Sp3000

11:48 PM

I updated my JRE and JDK but my IDE's still not recognising the funny -> arrows

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