The Nineteenth Byte

Poke

20:04

pax badges are available now

pax east, anyway

Pavel

@Poke Wat. Pax is late summer.

Oh

Poke

BOSTON, MA
APR 5 - 8, 2018

Pavel

@Poke I live really nearby where Pax Prime and Pax Dev happen

Also, wow, that is a long time in advance

Poke

@Pavel that's how they do

AdmBorkBork

@Pavel I would imagine they would need to be native to PowerShell, since the pipeline is an environment feature and not a language feature.

Pavel

20:13

@AdmBorkBork Apparantly you can by writing a class that extends System.Management.Automation.Cmdlet

Marcus Andrews

Is this not how to define functions?

x=gets.to_i
n=gets.to_i
f=->n{n>1?n*f[n-1]:1}
p f(x)/f(x-n)

Trying to codegolf some factorial stuff

nvm had to use [] not ()

Pavel

@MarcusAndrews That makes f a proc. Procs are called with either [] or .call.

Marcus Andrews

x=gets.to_i
f=->k{k>1?k*f[k-1]:1}
p f[x]/f[x-gets.to_i]

(reads two integers and computed x!/(x-n)!)

Pavel

# How to define a function:
def f n
n>1?n*f(n-1):1
end

Marcus Andrews

mm

Is this as short as I can get it?

(I suspect it is, or is at least pretty close)

caird coinheringaahing

20:27

Is there a prefix meaning "greater than 2"? Like "mon" for one and "dy"/"di" for two?

Adám

@cairdcoinheringaahing poly-?

AdmBorkBork

@Pavel Sure, that would make sense.

caird coinheringaahing

@Adám Hmm, that works. Thanks!

Mr. Xcoder

I smell Grammar hw :P

caird coinheringaahing

@Mr.Xcoder Nope

Mr. Xcoder

20:31

That was a joke anyway :D

caird coinheringaahing

Yeah, I'm trying to find a term for commands with an arity > 2. Nilads, monads, dyads, and polyds

Mr. Xcoder

> polyds

caird coinheringaahing

Pronounced "pol - ids"

Mr. Xcoder

lol I thought about multyads for a second

AdmBorkBork

I'd go for polyads myself

caird coinheringaahing

20:34

For some reason, I place emphasis on the "ads" part: "poly-ADS" rather than "POLY-ads"

Mr. Xcoder

What are the Atoms in Jelly that you (anyone that is willing to answer) have found hard to understand at first?

caird coinheringaahing

@Mr.Xcoder Uneval, z and y (I still don't fully understand the last two)

Mr. Xcoder

Well ¯\_(ツ)_/¯ what is Uneval?

caird coinheringaahing

@Mr.Xcoder Ṿ Cast to string

Mr. Xcoder

yeah just looked too

Marcus Andrews

20:36

What about 2 though? Poly can apply to 2 or more sometimes

Mr. Xcoder

Caird is looking for 2 or more (I think)

caird coinheringaahing

@Mr.Xcoder I would also mention the string ub

Marcus Andrews

Mm I thought he had said > 2 but if so, that works too

caird coinheringaahing

> greater than 2

Adám

@cairdcoinheringaahing I think I've seen the adjective polyadic.

Marcus Andrews

20:39

maybe multi? sightwordsgame.com/spelling/prefixes/prefix-multi

caird coinheringaahing

@Mr.Xcoder And the difference between F and Ẏ

Marcus Andrews

e.g. monomial, binomial, multinomial theorem, etc

caird coinheringaahing

ಠ_ಠ I feel like I'm listing too many :P

Mr. Xcoder

@cairdcoinheringaahing Thanks, I am making a list of "harder (to understand)" atoms rn

caird coinheringaahing

CMP: (for Jelly users) Have you ever used the t atom?

Mr. Xcoder

20:42

@cairdcoinheringaahing I haven't.

Also mold is hard to get

caird coinheringaahing

:O I used realised what ṃ is for!

Mr. Xcoder

@cairdcoinheringaahing i'd be glad to hear that

caird coinheringaahing

@Mr.Xcoder Do you know what ṃ is? Just curious to see how behind I am :P

Marcus Andrews

Any shorter way to do this in Python or Ruby?

n=input()
a=b=""
for i in range(n):l=raw_input();a+=l[i];b+=l[n-i-1]
print a,b

Mr. Xcoder

@cairdcoinheringaahing I don't.

Marcus Andrews

20:49

It's reading through a grid supplied in input and taking letters along the diagonal

Mr. Xcoder

@MarcusAndrews n-i-1 is the same as n+~i

caird coinheringaahing

@Mr.Xcoder CMC: Given n < 16, convert n to hex, using the digits 0-9A-F

Marcus Andrews

AxxE
xBFx
xGCx    = ABCD EFGH
HxxD

ah thanks, -1 char there

Mr. Xcoder

@cairdcoinheringaahing Brb

Why < 16??!?!

caird coinheringaahing

Because it doesn't work as I thought it did for > 16 ಠ_ಠ

Mr. Xcoder

20:51

@cairdcoinheringaahing 3 bytes I guess: ṃØH

caird coinheringaahing

@Mr.Xcoder Yep :P

> ṃ Base decompression; convert x to base length(y) then index into y.

Marcus Andrews

trying ruby but again wrong syntax

n=gets.to_i
a=b=""
for i in 0..n do
    l=gets.to_s
    a+=l[i]
    b+=l[n+~i]
end
p a b

Pavel

@MarcusAndrews p a b

Did you mean p a,b?

Marcus Andrews

maybe

the other stuff is failing atm

Pavel

@MarcusAndrews (0..n).each do |i| is prefered to for i in 0..n in ruby

@MarcusAndrews What error are you getting?

Marcus Andrews

20:55

implicit null conversion on the string bit

Pavel

You mean the a=b=""?

Could you just paste the error?

Marcus Andrews

the (0..n).each thing is longer though

"no implicit conversion of nil into String (TypeError)"

on the line l=gets.to_s

Pavel

@MarcusAndrews No it isn't, because you can use { instead of do when calling each.

Marcus Andrews

Ah the minus 1

n=gets.to_i
a=b=""
for i in 0..n-1 do
    l=gets.to_s
    a+=l[i]
    b+=l[n+~i]
end
print a+" "+b

n=gets.to_i
a=b=""
(0..n).each do |i|{l=gets.to_s;a+=l[i];b+=l[n+~i]}
print a+" "+b

Pavel

@MarcusAndrews 0...n is shorter than 0..n-1

Marcus Andrews

20:58

ahh, interesting syntax

Pavel

@MarcusAndrews That's just completely wrong block syntax.

(0..n).each{|i|l=gets.to_s;a+=l[i];b+=l[n+~i]}

Or (0...n).

Marcus Andrews

gotcha

is the print the shortest possible?

space separated so I just did a+" "+b

Pavel

$><< is shorter than print

Marcus Andrews

also more interesting syntax

Pavel

It's two symbols, $> <<

Or STDOUT APPEND

Marcus Andrews

21:02

send the righthand contents as input to $> which must be stdout?

Pavel

yep.

Why print, anyway? The normal way of printing in Ruby is puts.

@MarcusAndrews $< is STDIN, $<.read is the shortest way of getting all the input. $<.each_line iterates over lines.

Marcus Andrews

so $<.map{...} applies a mapping to every line from stdin?

$<.map{|l| p l} (or do whatever else with the line)

caird coinheringaahing

@Mr.Xcoder Cartesian product and power

Adám

21:17

@cairdcoinheringaahing APL: ⎕⊃⎕D,⎕A (assumes ⎕IO←0)

Anonymous

@cairdcoinheringaahing Actually, 2 bytes: ─û (hex, uppercase)

Mr. Xcoder

@cairdcoinheringaahing Do you want write access to the repository?

caird coinheringaahing

@Mr.Xcoder Sure, why not?

Mr. Xcoder

(or did I make the wiki publically editable?)

@cairdcoinheringaahing I'll give you write access, but could you please tell me if the wiki can now be edited without write access?

caird coinheringaahing

@Mr.Xcoder Sure, testing

@Mr.Xcoder No, it can't be edited

Mr. Xcoder

21:22

Good, thanks

@cairdcoinheringaahing Done

caird coinheringaahing

@Mr.Xcoder Thanks

New Sandboxed Posts

21:34

0

A: Sandbox for Proposed Challenges

Numbers where n! - 1 or n! + 1 is a prime Combination of OEIS A002981 and OEIS A002982 Sandbox note: This is my first code-golf challenge; feedback is highly appreciated. Output the nth non-negative integer m where m! - 1 or m! + 1 is a prime. The first few numbers of the sequence are 0, 1, ...

Marcus Andrews

how about something like this

P={}
i=input
for _ in' '*int(i()):
 for j in range(*map(int,i().split())):P[j]=1
print(len(P))

input looks like
3
2 5
8 13
14 20

each row is a range of time

at the end, output number of hours with at least one person present

e.g. 2 5 means someone is present at hours 2, 3, 4, 5 (total of 4 here)

so output for that one above is 14

AdmBorkBork

@cairdcoinheringaahing PowerShell, ridiculously long -- ("{0:x}"-f$args[0]).ToUpper()

However, it works for n > 16, so there's that at least

Marcus Andrews

trying the ruby approach Pavel taught earlier

P={}
gets.to_i.times{a,b=gets.split.map(&:to_i);(a...b).each{|i|P[i]=1}}
p P.size

AdmBorkBork

It's using the -f format operator

Uriel

@MarcusAndrews i=input saved you no byte (nput goes for the first, i=i\n for the second)

AdmBorkBork

21:45

Used for things like displaying as a percentage, or as a dollar-and-cents amount, or to a certain precision, etc. Here, we're converting to hex with the x specifier.

Marcus Andrews

I usually do it out of habit if there's more than one input simply because it doesn't hurt / it's mindless to do

but i take the point, yeah

can the ruby be shortened?

Marcus Andrews

22:08

What was that n+1 trick again?

-~n or something?

yep

Pavel

Uh, where is a assigned and what is that program supposed to do?

Marcus Andrews

right now, tallest pyramid given a certain number of blocks, as well as number of blocks left over

n=input()
t=int(((8*n+1)**.5-1)/2)
print t,n-t*-~t/2

solves the equation t(t+1)/2 <= n

Pavel

Looks like t<=n*2-1

Marcus Andrews

ruby
n=gets.to_i
t=(((8*n+1)**0.5-1)/2).to_i
print t,' ',n-t*-~t/2

(puts places the two items on separate lines, print same line)

oh wait, that print trick

Pavel

Why are you using print again

Don't use print in ruby

Marcus Andrews

22:13

weird didn't work this time anyway

unexpected ',',

Pavel

In production code you should use puts most of the time.

Marcus Andrews

this is for codegolfing

but yes i agree

Pavel

puts is still shorter than print, and doesn't have $><<'s order of operations priority so it's sometimes better.

Marcus Andrews

but placing two numbers on the same line, separated by space?

Pavel

Ah, I see, the arguments to print shouldn't be seperated.

I understand now

Marcus Andrews

22:15

funnily enough the python is shorter

n=input()
t=int(((8*n+1)**.5-1)/2)
print t,n-t*-~t/2

Pavel

$><<[t,n-t*-~t/2]*" "

No that's a bit longer I think

Marcus Andrews

the python is 53

the other is 61

Pavel

What exactly is the problem, I'm still not following what all the numbers are for.

Marcus Andrews

"tallest pyramid given a certain number of blocks, as well as number of blocks left over"

pyramid requires 1+2+3+4+... blocks

so if you have n blocks you need to solve for t(t+1)/2 <= n

to get the height of the pyramid

and then n-t(t+1)/2 tells you the blocks left over

for example if I have 12 blocks, I can a pyramid with 1+2+3+4 = 10 blocks (If I added layer 5 I'd need 15 blocks, which I don't have). So I can make a pyramid of height 4, with 12 - 10 = 2 blocks left over

Pavel

Hmmm

Marcus Andrews

22:22

and the solution to the block inequality is t = (1/2) * (sqrt(8n + 1) - 1)

New Main Posts

22:42

0

Q: Tips for golfing in QBasic

What?! This question doesn't exist yet? What general tips do you have for golfing in QBasic? I'm looking for ideas that can be applied to code golf problems in general that are at least somewhat specific to QBasic (e.g. "remove comments" is not an answer).

Bald Bantha

23:37

wait what ever happened to the ppcg home page? you cant get to chat from it easily anymore

I have a feeling this happened a while ago I just haven't been on here for a while

Adám

@BaldBantha SE icon in top left corner>chat.

Bald Bantha

yeah the drop down thing disapeared

Adám

@BaldBantha No, SE just rolled out a new navbar not long ago.

@BaldBantha It's weird. On SE.se it is still the old style. And on SO, the top left icon goes to SO, not SE like all other SE sites.

Mistah Figgins

23:57

Grr! Why doesn’t befunge 98 have a decent interpreter? The s command should put the v in that empty space, sending the IP down! tio.run/##S0pNK81LT9W1tNAtqAQz//@vK1Yw1HPgUlCwM9Jz@P@/DAA

Never mind, apparently it just doesn’t execute it

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