The Nineteenth Byte

New Sandboxed Posts

18:21

0

Largest Prime Exponents Given an integer n >= 2, output the largest exponent in its prime factorization. This is OEIS sequence A051903. Example Let n = 144. Its prime factorization is 2^4 * 3^2. The largest exponent is 4. Test Cases 2 -> 1 3 -> 1 4 -> 2 5 -> 1 6 -> 1 7 -> 1 8 -> 3 9 -> 2 10 ->...

Erik the Outgolfer

@Mego hmm...not sure about your latest sandboxed challenge

Anonymous

@EriktheOutgolfer Care to offer any more insight?

Erik the Outgolfer

looks like it's combining two unrelated challenges...?

like, prime exponents and max

(faq-proposed: let's define how related is "related")

Anonymous

The inspiration came from thinking about the runtime complexity of simple trial division to find all of the prime factors of an integer

Anonymous

(see above)

Socratic Phoenix

18:25

but its an OEIS sequence so by the OEIS postulate of PPCG it must be good?

Erik the Outgolfer

hmm...maybe adding some tags in there can help judging

not really sure if it's code-golf or fastest-code or even fastest-algorithm?

Anonymous

@EriktheOutgolfer By Sandbox custom, no tags implies code golf

Erik the Outgolfer

alright

DJMcMayhem

Regex Challenge: Replace an odd-length of 'a's with the same length of 'b's. Test case: "acaacaaacaaaacaaaaa" --> "bcaacbbbcaaaacbbbbb"

Erik the Outgolfer

@Mego hmm...

looks like it's going to be a couple of built-ins in most commonly used languages

Anonymous

18:29

@EriktheOutgolfer So are most number theory challenges. C'est la vie.

AdmBorkBork

@NewSandboxedPosts Boy, that sure seems familiar, but I can't find a dupe.

Erik the Outgolfer

my experience must be lying then

also what admborkbork said

Anonymous

I did a pretty thorough dupe search before sandboxing it, but found nothing. I sandboxed it rather than posting it directly to main in case I missed one.

Erik the Outgolfer

I'd suggest keeping it in the sandbox for at least 72 hours, it's highly possible there's already a dupe

that is, a red light started blinking for me when I saw that challenge, not sure about others

Mr. Xcoder

18:45

CMC: Given a non-empty list of positive integers, compute the median of the medians of its prefixes

Erik the Outgolfer

vtc

Mr. Xcoder

[12, 39, 29, 92, 29] -> 29

@EriktheOutgolfer VTC as "biased towards Jelly"?

Erik the Outgolfer

as dup

Mr. Xcoder

That too, but I don't really care at all

Erik the Outgolfer

btw @Mr.Xcoder can you give a test case where the median of the medians of its prefixes would be different from the median itself?

Mr. Xcoder

18:49

@EriktheOutgolfer [100, 29, 39, 12, 39, 29, 92, 29, 3267, 73, 28, 38] -> 39 (the median is 38.5)

the obvious solution is 5 bytes in Jelly (ÆṁƤÆṁ).

DJMcMayhem

Spotted today on my SO profile

3spoopy5me

Erik the Outgolfer

> poop

Socratic Phoenix

3 or 2?

Erik the Outgolfer

it was so spooky?

DJMcMayhem

It's (n)spoo[kp]y(n+2)me

Mr. Xcoder

18:53

@DJMcMayhem Lol you vote 3 times less than I do (I have 1753 votes cast)

DJMcMayhem

Although I have to say, -1spooky1me looks a little weird.

Erik the Outgolfer

how about -3spooky-1me then

Anonymous

∞spooky∞me

Mr. Xcoder

∞5p00ky∞m3

Neil

@DJMcMayhem 24 bytes

Anonymous

18:55

Relevant:

Anonymous

35

Q: Halloween Golf: The 2spooky4me Challenge!

A current internet meme is to type 2spooky4me, with a second person typing 3spooky5me, following the (n)spooky(n+2)me pattern. Your mission is to implement this pattern in your chosen language. You should write a program or function that takes a value n (from standard input, as a function argume...

Erik the Outgolfer

@Mego except that 1) I think $\infty\ne\infty+2$ 2) come on :p

Mr. Xcoder

$\infty\ne\infty + 2$ ಠ_ಠ

You cannot just add something to infinity...

Neil

depends on your infinity

Mr. Xcoder

It does...

Erik the Outgolfer

18:57

basically infinity isn't even an "n", it's a mathematical concept

Mr. Xcoder

True.

Neil

adding 2 to IEEE or cardinal infinity just gives you infinity, but adding 2 to ordinal or surreal infinity gives you a new number

Mr. Xcoder

Hence why you cannot perform arithmetic operations with it.

Anonymous

@EriktheOutgolfer Nope. Both normal extensions to the real line to include infinity (the extended real number line and the projectively extended real line) define ∞+n=∞ for all n (except the extended real number line defines ∞+(-∞)=0).

Mr. Xcoder

@Neil Namely the things with Alephs and stuff right? And cardinal numbers

Neil

18:58

no, not alephs

Anonymous

@Mr.Xcoder Sure you can! You just need a new number system

Mr. Xcoder

But cardinals

Sherlock9

@Mr.Xcoder What do you mean by prefixes here?

Mr. Xcoder

@Sherlock9 [1,2,3,4] has the prefixes [[1], [1,2], [1,2,3], [1,2,3,4]]

@Neil So like ω+1?

Sherlock9

Okay so [29, 40, 55, 12, 16] => [29, 34.5, 40, 34.5, 29] -> 34.5, correct?

Mr. Xcoder

19:02

@Sherlock9 Yes.

Sherlock9

Interesting

Mr. Xcoder

If you want more test cases, you can use this Jelly program.

AdmBorkBork

@Mr.Xcoder I must not be understanding. Doesn't (29+40+55)/3 equal 41.(3)?

Mr. Xcoder

@AdmBorkBork Where does that 29+40+55 come from?!

AdmBorkBork

That's the third prefix of [29,40,55,12,16] isn't it?

Mr. Xcoder

19:11

Let me write a worked example.

AdmBorkBork

29/1 = 29 ... (29+40)/2 = 34.5 ... right?

Mr. Xcoder

@AdmBorkBork [29, 40, 55, 12, 16] has the following prefixes: [[29], [29, 40], [29, 40, 55], [29, 40, 55, 12], [29, 40, 55, 12, 16]]. The medians of each are [29, 34.5, 40, 34.5, 29]. Now if you take the median of this list: 34.5.

@AdmBorkBork Wait. Not the arithmetic mean, the median.

AdmBorkBork

Oh, durr

lol

Mr. Xcoder

CMQ: Are there vectors in maths as well or just in Physics and science?

AdmBorkBork

Single-column or single-row matrices are called "vectors"

Mr. Xcoder

19:17

Oh really?!

thanks for the response Btw!

I assume they're quite different from the physical meaning

AdmBorkBork

There's also a whole vector analysis involving radians and polar coordinates and whatnot

Mr. Xcoder

Ok I should reeeeally document myself about that

AdmBorkBork

and lots of calculus

IIRC, vector analysis was lots of calculus

quartata

@Mr.Xcoder The vectors you are thinking of are Euclidean vectors

Mr. Xcoder

@AdmBorkBork Well since it's mathematics, that's pretty much implied

quartata

19:20

They're still vectors

Mr. Xcoder

@quartata I kinda understood.

HyperNeutrino

in pure math a vector is just a coordinate point

A tuple, if you want to think of it that way.

Mr. Xcoder

How is that a vector, how does that have a "length" for example?

Or am I misunderstanding badly?

AdmBorkBork

From the origin

Mr. Xcoder

I understood now.

AdmBorkBork

19:22

What's more fun is multiplying vectors together

Mr. Xcoder

So these are Euclidean vectors.

quartata

Norm (mathematics)

In linear algebra, functional analysis, and related areas of mathematics, a norm is a function that assigns a strictly positive length or size to each vector in a vector space—save for the zero vector, which is assigned a length of zero. A seminorm, on the other hand, is allowed to assign zero length to some non-zero vectors (in addition to the zero vector). A norm must also satisfy certain properties pertaining to scalability and additivity which are given in the formal definition below. A simple example is two dimensional Euclidean space R2 equipped with the "Euclidean norm" (see below) Elements...

HyperNeutrino

In applied math a vector is usually considered the directed line segment from the origin to the equivalent point but there's really no difference so in pure math it's the exact same thing

quartata

The norm of a Euclidean vector is the usual distance from the origin you've seen before

Mr. Xcoder

I see.

quartata

19:26

This is kind of like a group if you've seen that before: a vector space with an associated norm

HyperNeutrino

when your city government runs a 15+ minute train track barricade test in the middle of the day and you get stuck ;_;

Mr. Xcoder

uhm, why does that sound very familiar?

HyperNeutrino

?

(scrolls up to make sure I didn't complain about that already)

Mr. Xcoder

@HyperNeutrino That happened to me like 2 days ago :P

HyperNeutrino

oh rip :P

coincidence?

it must be the aliens...:P

Mr. Xcoder

19:36

Maybe

HyperNeutrino

no it's the aliens

but yeah my school bus got stuck and then after like 12 minutes most people decided to leave and walk back home (25-35 mins) and then we passed them all lol

Mr. Xcoder

I am so so glad I don't have to take the bus to and from school :)

HyperNeutrino

I wish I lived close enough to walk/bike :P

Mr. Xcoder

Just a 20 min walk here

HyperNeutrino

nice it takes me 25 mins to bike to school

bus ride is like 20 minutes there 18 back or so

dzaima

19:38

~8 minutes here :p

Mr. Xcoder

I wish we had a bike-friendly country

HyperNeutrino

I mean then again I live on the edge of my city next to the Mennonite-heavy area so there really aren't high schools close to here. The elementary school in my region is relatively new because this place wasn't very populated just ~50 years ago

for some reason unbeknownst to me, my bus takes the highway to school in the morning but not back in the afternoon, even though it's the same bus, people, driver, and pickup/dropoff

Mr. Xcoder

@totallyhuman Huh you're finally totallyhuman again ;-;

HyperNeutrino

he stopped crying

Mr. Xcoder

Brb watching a vid by Dyalog

HyperNeutrino

19:43

lol

Mr. Xcoder

CMC: Given a square matrix and two coordinates, return the list of neighbours of that element.

HyperNeutrino

toroidal?

Mr. Xcoder

Making test cases

@HyperNeutrino Sorry no idea.

[[1, 2, 3], [4, 5, 6], [5, 6, 7]], [1,1] -> [2, 4, 6, 6] (order is irrelevant)

[[1, 2, 3], [4, 5, 6], [5, 6, 7]], [0,0] -> [2, 4]

Anonymous

@Mr.Xcoder Toroidal means that the elements wrap around for neighbor detection

HyperNeutrino

ok so not toroidal

Mr. Xcoder

19:50

(the horizontal and vertical neighbours, the diagonal ones do not count)

HyperNeutrino

ok

oh nice it's even a square

Anonymous

@Mr.Xcoder So the von Neumann neighborhood, not the Moore neighborhood

Mr. Xcoder

Probably, I have absolutely no idea what all those fancy terms mean.

John Dvorak

I keep confusing the two

Mr. Xcoder

@HyperNeutrino I didn't wanna be mean; Also you can assume the coordinates are in the matrix, but there might be no neighbours in case the element is "at the margins"

Sherlock9

19:52

von Neumann neighborhood is just the horizontal and vertical, Moore neighborhood includes the diagonal

HyperNeutrino

ah ok

Sherlock9

Conway's Game Of Life uses Moore neighborhoods, for examples

Mr. Xcoder

Kinda got it

Anonymous

@Mr.Xcoder I got to learn all of these fancy terms during QFT work

John Dvorak

Is the matrix guaranteed to be at least 2x2?

Mr. Xcoder

19:53

@JohnDvorak No.

durron597

too broad? too clever for my own good? codegolf.meta.stackexchange.com/a/14087/17249

John Dvorak

at least 1x1?

Mr. Xcoder

It is guaranteed to be at least 1x1.

durron597

p.s. hi room :)

HyperNeutrino

hello

the room does not greet you back

Mr. Xcoder

19:54

Hello

HyperNeutrino

0/10 way too broad

durron597

@HyperNeutrino yeah i thought so. :-/

HyperNeutrino

I mean, language analysis is something that computers are still struggling with and we're not about to write a perfect language analyzer :P Also, it would need to be extremely well specified.

Mr. Xcoder

Yeah it is extremely broad

Anonymous

Man, not toroidal is way harder in Python than toroidal

Mr. Xcoder

19:56

@Mego How come?

durron597

@HyperNeutrino the idea is like, take a language like CJam or Pyth and use those commands to do the job of the english sentence

Anonymous

@Mr.Xcoder Because Python lists are toroidal with negative indices. a[-1] is the last element in the list.

durron597

but i didn't want to require people to only use some subset of languages

Mr. Xcoder

@Mego I know.

AdmBorkBork

@durron597 Ooo, PowerShell may actually have a chance at this

HyperNeutrino

19:56

@Mego be glad it's not jelly where indices wrap around both sides lol

Mr. Xcoder

That shouldn't be a huge problem though

durron597

i definitely am looking for people to give feedback on how to make it not too broad

Anonymous

Properly handling wraparound is much longer than not

durron597

but i accept the possibility it may be impossible

Mr. Xcoder

@Mego Indeed

AdmBorkBork

19:58

also, Inform is basically designed for that challenge

Anonymous

For example, von Neumann neighborhood with toroidal matrices is 54 bytes: lambda m,a,b:[m[a+1][b],m[a][b+1],m[a-1][b],m[a][b-1]]

durron597

@AdmBorkBork i did also consider banning languages that are explicitly natural language languages

HyperNeutrino

@Mego wouldn't you need % to prevent index out of error?

New Sandboxed Posts

0

A: Sandbox for Proposed Challenges

Behavior Driven Golfing Context From wikipedia (emphasis mine): Behavior Driven Development (BDD) is largely facilitated through the use of a simple domain-specific language (DSL) using natural language constructs (e.g., English-like sentences) that can express the behavior and the expected out...

Mr. Xcoder

@Mego Best I could is Python 2, 94 bytes lambda m,a,b:[m[a+1][b]]*(a<len(m))+[m[a][b+1]]*(b<len(m))+[m[a-1][b]]*(a>0)+[m[a][b-1]‌]*(b>0)

Anonymous

20:02

@HyperNeutrino True...

HyperNeutrino

this should be a built-in for enlist

Mr. Xcoder

implements in Cthulhu

HyperNeutrino

8 builtins for toroidal or not, von Neumann or Moore, and get neighbor indices or get the neighbors rather than their indices

I wonder whether Enlist will turn out more like Cthulhu or Jelly

Mr. Xcoder

@HyperNeutrino Cthulhu is not even a thing (and its hard to say whether I will ever finish it (during the current era))

HyperNeutrino

oh

Mr. Xcoder

20:04

I mean, I have a good part of the built-ins and the vectorization architecture

And BTW Cthulhu becomes stack-based!!!

(prefix is a headache)

HyperNeutrino

I think Enlist will be more similar to Jelly because it uses the same tacit system

cool

Mr. Xcoder

gtg o/

MetaEd

Never execute the Cthulhu WAKE statement.

Mr. Xcoder

@MetaEd Lol Cthulhu does have a WAKE built-in (that basically pushes the current time)

HyperNeutrino

o/

Anonymous

20:08

@Mr.Xcoder Python, 112 bytes: lambda m,a,b:[m[a+x][b+y]for x in(-1,0,1)for y in(-1,0,1)if len(m[x])>y+b>=0and len(m)>x+a>=0and abs(x)!=abs(y)]

Anonymous

Version doesn't actually matter

Anonymous

But it's much worse than the above version

HyperNeutrino

CMC: Toroidal Moore neighborhood

given a rectangular matrix and a coordinate pair in the range

Cyoce

20:36

Yikes. 19 bytes in J-uby just to get [-1,0,1] × [-1,0,1]: ~:product.D^(-1!~1)

Anonymous

@HyperNeutrino Python, 94 bytes: lambda m,a,b:[m[(a+x)%len(m)][(b+y)%len(m[x])]for x in(-1,0,1)for y in(-1,0,1)if(x==0)^(y==0)]

New Main Posts

6

Q: Binary Prime-Chunks

We are searching for a sequence Take the natural numbers 1,2,3,4,5,6,7,8,9,10,11,12,13,14... Convert to base-2 1,10,11,100,101,110,111,1000,1001,1010,1011,1100,1101,1110... Concatenate the above numbers 110111001011101111000100110101011110011011110... Partition this number in Prime-Chunks...

code-golf sequence binary

Leaky Nun

@DJMcMayhem hi

DJMcMayhem

o/

Pavel

21:46

Can anyone who knows C explain to me why converting 3 to a float yields 0.000000

Leaky Nun

@Pavel should have something to do with how they store floats

Single-precision floating-point format

Single-precision floating-point format is a computer number format that occupies 4 bytes (32 bits) in computer memory and represents a wide dynamic range of values by using a floating point. In IEEE 754-2008 the 32-bit base-2 format is officially referred to as binary32. It was called single in IEEE 754-1985. In older computers, different floating-point formats of 4 bytes were used, e.g., GW-BASIC's single-precision data type was the 32-bit MBF floating-point format. One of the first programming languages to provide single- and double-precision floating-point data types was Fortran. Before the...

(solution is use 3.0 instead if you want to stop here)

Pavel

@LeakyNun I'm not looking to solve a problem I'm just wierded out by this happening in the first place

Leaky Nun

good, then I can continue

Pavel

Also, abs(-3.5) is 1.

(And yes I know I'm supposed to use fabs)

Leaky Nun

hmm, my theory can't explain that

Pavel

21:53

Even though printf("%d", -3.5); gives -333662952, so I'd expect abs(-3.5) to give 333662952, which would atleast make some sense.

Leaky Nun

@Pavel that's another weird behaviour

Pavel

C is a weird language.

Leaky Nun

22:11

I give up

Helka Homba

Assuming you don't need to enter text much, would you guys rather control a program with only the mouse or only the keyboard?

Eric Tressler

@HelkaHomba I'm voting to close your question as too broad.

the answer definitely can't be keyboard, because consider paint programs. it also definitely can't be mouse, because consider Nethack

Helka Homba

yeah

Pavel

22:56

I'd say mouse.

@EricTressler Why not play Nethack with a mouse? Click where you want to go, click through inventory, click commands. It would be more tedious than the normal nethack, but totally doable

Eric Tressler

@Pavel he asked which we would rather use. Unless you would rather play Nethack with a mouse than with a keyboard, my example is valid

Pavel

I'd rather have to use a mouse for everything than keyboard for everything

@HelkaHomba How about "Xbox controller"

Eric Tressler

fair enough. what about a wiimote

or power glove

ASCII-only

23:12

@LeakyNun Nope

@LeakyNun nope

Riker

@quartata you still boycotting tf2?

quartata

@Riker "boycotting"?

Riker

I thought you boycotted it

quartata

no

Riker

in return for the bad updates

huh nvm then

ASCII-only

23:19

something here maybe @Pavel

Riker

trying jungle update now :D

quartata

I think they're making good updates

Riker

ah

quartata

Maybe you're thinking of overwatch

Riker

just not enough?

@quartata maybe it was that I don't remember

you did notice the big update though right >_>

caird coinheringaahing

23:19

Ugh, I just finished designing modifiers in Levant, and want to throw up.

quartata

yes

Riker

they reset casual ranks? wat

ASCII-only

@cairdcoinheringaahing ... that just means you wrote your language badly

3

Riker

pro-tip: throwing up is not golfy

ASCII-only

@cairdcoinheringaahing what are modifiers like

caird coinheringaahing

23:28

@ASCII-only They're basically quicks in Jelly. They modify the behaviour of an atom

Leaky Nun

@ASCII-only nope

caird coinheringaahing

The reason I want to throw up isn't the way they're designed, it's thinking about how I'm going to create the parser.

ASCII-only

@cairdcoinheringaahing Well that's what I thought in the first place

@cairdcoinheringaahing Just copy Jelly

caird coinheringaahing

@ASCII-only It's aiming to beat/tie Jelly, and I can't understand Dennis' regexes :P

ASCII-only

> beat/tie Jelly

good luck

caird coinheringaahing

23:32

Thanks :P I've tried out some sample programs to see what the results would be and it's looking pretty good. I think just over 50% of the challenges in JHT were won by Levant

ASCII-only

23:44

:O

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