The Nineteenth Byte

muddyfish

7:00 PM

Anyone here know how to use the python c api to turn a c struct into a python memoryview?

Leaky Nun

@Sherlock9 which?

Sherlock9

Your second sequence (so that the sum is divisible by the length)

Bald Bantha

I'm like the only one on the PPCG minecraft server recently. Built an awsome base though...

Downgoat

this look ready to post?:

5

A: Sandbox for Proposed Challenges

Dividing Strings Division with numbers is great: 6 / 3 = 2, but have you ever wanted to divide strings? In this challenge you will, given two strings (s and t) divide s by t Challenge Given a string, s, find the substring in which t is repeated the most times (non-overlapping), return the amou...

Sherlock9

@BaldBantha Oh dang. I should visit the server soon

New Main Posts

7:07 PM

0

Q: Smallest positive number whose y-th power is divisible by x

Task Given positive integers x and y, find the smallest positive number whose y-th power is divisible by x. Example Given x=96 and y=2, the output should be 24 since 24 is the smallest positive n satisfying n^2 is divisible by 96. Testcases x y output 26 2 26 96 2 24 32 3 8 64 9 2 27 3 3 ...

Leaky Nun

That's fast

@Sherlock9 Could you do me a favour by writing my explanation? Your style is much better

Sherlock9

Sure :D

On the triangle question, right?

Leaky Nun

Yes

@Sherlock9 Are you still writing? Because I golfed one byte

(by revolutionizing the approach)

Sorry for wasting your effort

Sherlock9

Yeah, I'm still writing

Nah

I'm happy to work on the revised version

Leaky Nun

Thanks, submitted revised version

Thank you.

Sherlock9

7:20 PM

You're welcome o7

Releasing Helium Nuclei

7:30 PM

> powdiv.c:1:28: error: invalid operands to binary % (have ‘double’ and ‘int’)
i;f(x,y){i=0;while(pow(i,y)%x)i++;return i;}
~~~~~~~~^

wat

pow() returns double?!

Leaky Nun

double pow(double x, double y)

Not only does it return double, but also takes double

tutorialspoint.com/c_standard_library/c_function_pow.htm

Releasing Helium Nuclei

i can use man thx

Downgoat

> typeof NaN
< "number"

I thoguht NaN was specificaly not a number

2

Releasing Helium Nuclei

c doesnt have this problem

Downgoat

I mean it explicitly says "Not a Number", in fact what else is it

Releasing Helium Nuclei

7:36 PM

bcoz c doesnt have typeof xD

Downgoat

so much wat

@ReleasingHeliumNuclei sizeof(NaN) == sizeof(int)

Releasing Helium Nuclei

@Downgoat no NaN neither

Leaky Nun

@Downgoat Look, all numbers are floats which occupy the same amount of spaces

Downgoat

@ReleasingHeliumNuclei #include <math.h>

Leaky Nun

and NaN is a number in the sense that it is stored in floating point

Releasing Helium Nuclei

7:42 PM

i3 bindsyms dont work with numlock

vim borks without numlock

halp

El'endia Starman

@Downgoat NaNs are usually represented internally as a floating point number with a special byte sequence. But I agree, JavaScript shouldn't have its type as "number".

Hmm, well, Python has it as type float:

>>> type(float('nan'))
<class 'float'>

>>> import numpy
>>> numpy.nan
nan
>>> type(numpy.nan)
<class 'float'>

Sherlock9

@LeakyNun What do you mean by the second one being wrong?

quartata

Yeah, it's just a special IEEE float. Same thing with positive and negative infinity

Leaky Nun

@Sherlock9 try 32 3

The fix would require one more byte

Downgoat

@El'endiaStarman JavaScript typeof is just generally messed up. typeof [1,2,3] is "object".

new String("foo") === "foo" === false

El'endia Starman

7:49 PM

@Downgoat JS only has three types, right? Integer, string, object.

Downgoat

by spec no, but by implementation yes. typeof only returns number, String or Object. JavaScript has no understanding of "type"

El'endia Starman

I was trying to recreate @Sp3000's trick of erroring out with ><> on Helka's printable ASCII challenge, and accidentally made an infinite "moo" printer (with a few side effects). :P

Sp3000

@LeakyNun If x = 1 is valid input it should probably be a test case

Ditto y = 1

Sherlock9

@LeakyNun You post Approach 3 just as I finish typing up the explanations for Approaches 0 and 2

Excellent timing :D

Might as well get Approach 2 in there as well

Leaky Nun

I'm the master of timing.

mınxomaτ

8:07 PM

theregister.co.uk/2016/08/19/…

WTF

feersum

> A homeless IT consultant

That's the weird part right?

quartata

Yeah, I had to read that twice...

GamrCorps

Does anyone here know how I can open an image in python, and apply a function to every pixel? E.g. I want to apply the function convert(r,g,b): ... return (new_r,new_g,new_b) to every pixel of the image.

Leaky Nun

@Mego How exactly do the scopes of functions in Actually work? For n, the global stack is available; for ╓, the global stack is hidden.

quartata

@GamrCorps Use PIL

Then you can just do Image.open(...).getdata() I think

That should give you a 2D array of the pixels

Sherlock9

8:20 PM

Goodnight everyone

Leaky Nun

8

Q: Smallest positive number whose y-th power is divisible by x

Task Given integers x and y which are both at least 2, find the smallest positive number whose y-th power is divisible by x. Example Given x=96 and y=2, the output should be 24 since 24 is the smallest positive n satisfying n^2 is divisible by 96. Testcases x y output 26 2 26 96 2 24 32 3 4...

code-golf integer

Saltvote?

Rohan Jhunjhunwala

</shameless self advertising>

(I didnt downvote)

+1

Dennis

@LeakyNun Not my downvote, but the challenge is a bit unclear atm. You don't specify what values x and y can take (positive, non-negative, both, only integers greater than 1, etc.), and you don't provide a definition of divisibility (not really necessary if only positive integers have to be supported).

Leaky Nun

> Given integers x and y which are both at least 2

Dennis

Oh, that was added after I read the spec...

Leaky Nun

8:34 PM

@Dennis It was "positive integer"

Dennis

OK, but 1 was still a potential edge case. The downvote was cast before the edit.

Leaky Nun

That is true.

feersum

Somebody must have been disappointed that it's not an alphabet pattern.

trichoplax

@Downgoat I thought it was a great grand number

Downgoat

o_O we don't have an alphabet tag

imo id be useful

El'endia Starman

8:46 PM

@Downgoat I was actually just thinking about that earlier today. I think it suffers from the same issue as an oeis tag though: it's a meta-tag, which are discouraged.

Most alphabet challenges can be done with any sequence of characters.

Downgoat

i dont think its really a meta-tag. the sequence doesn't have to do with OEIS at all but alphabet questions have to do with alphabet

@El'endiaStarman ok that is true but usually they are designed for 26 chars

El'endia Starman

Another thing to consider: we didn't need an alphabet tag for five years.

Dennis

It also gives the impression that creating a ton of alphabet challenges is encouraged. I liked most of them, but the latest one is at +13/-6.

Downgoat

i dont see why alphabet chalenges are bad. we have a sequence challenge almost every day but that's not a problem :/

@El'endiaStarman are you saying we dont need any new tags .__.

El'endia Starman

@Downgoat It's probably that they're all variations on a theme. Sequences often require wildly different algorithms.

flawr

8:52 PM

@Downgoat they get boring, and are quite often very low effort

El'endia Starman

@Downgoat More like, we've surely had challenges that involved the alphabet in the past, no? We only thought of it because we recently had a lot of alphabet challenges.

Downgoat

@El'endiaStarman only thing the same with alphabet challenges is that the outputted chars about A-Z, hardly the same algorithm.

trichoplax

I don't have a problem with alphabet challenges, but I can't imagine anyone following the alphabet tag, since it doesn't tell you anything about the challenge

Dennis

@Downgoat There's a constant amount of code you need to generate the alphabet, which can be non-trivial in some languages. Doing that once for every challenge gets repetetive.

trichoplax

Beyond string, I don't see a use for listing which particular characters a challenge uses in a tag.

El'endia Starman

8:54 PM

In a sense, alphabet challenges are all slightly chameleon challenges - they're really layout challenges.

trichoplax

So far...

El'endia Starman

Oooh, maybe that could be a tag - layout or something like that.

trichoplax

Does ascii-art cover it?

Dennis

That would make a lot more sense than alphabet.

trichoplax

My last challenge was denounced as an alphabet challenge by some, but wasn't about layout but about probability

I think there can be a broader range of alphabet themed challenges, which makes a tag even less meaningful

Dennis

8:56 PM

@trichoplax Sort of. ASCII art usually has a more complex shape and less related characters.

We definitely don't need a tag for themes, no.

trichoplax

@Dennis perhaps it could just use two tags, like boring ascii-art

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