The Nineteenth Byte

Wezl

00:36

codegolf.stackexchange.com/review/suggested-edits/57789 I edited an answer mistakenly, and now I'm trying to fix it

is there a way for me to do this without unfairly gaining rep?

pppery

01:50

A moderator can retroactively reject the edit, denying you the two rep.

Razetime

03:55

@Lyxal I agree

@Neil your answer is correct

pppery

04:53

7 minutes

HyperNeutrino

hope i don't choke again

6

ASCII-only

@HyperNeutrino same :(

HyperNeutrino

note to self: negative numbers are a lie

Redwolf Programs

5

pppery

Of course, now today's challenge will have nothing to do with negative numbers

HyperNeutrino

04:55

lol yeah ofc, i'm gonna mess up on a completely new thing

Redwolf Programs

4

ASCII-only

note to self: remember how to type

pppery

You just did.

ASCII-only

o

big brain

Lyxal

guys how do i type

ASCII-only

04:56

note to self: don't write bugs

pppery

20 secs ago, by pppery

You just did.

Lyxal

idk how to type.

HyperNeutrino

noet to slef: dont' mae ktypos

3

ASCII-only

ez 2 minutes

note to self: be betaveros

HyperNeutrino

speeeeeeeeed

ASCII-only

04:57

betaveros is just algo god

pppery

no, xiaowuc1 is better

apparently

HyperNeutrino

no their secret is they actually just do it all in their head so they don't even need to code

Lyxal

note to self: make a note to self saying "note to self: make a note to self saying "note to self: make a note to self saying "note to self: make a note to self saying "note to self: make a note to self saying "note to self: make a note to self saying "note to self: make a note to self saying "note to self: make a note to self saying "...

4

Redwolf Programs

"I'm trying a new strategy where I mess up on the logic for an hour then realize I made a typo on line 4"

pppery

2

ASCII-only

04:58

@RedwolfPrograms me basically. part 2 yesterday, small bug cost me 10 mins

@Lyxal nice haskell infinite quine

Redwolf Programs

1

ASCII-only

note to self: how to read

i literally dont read the prompt

Redwolf Programs

.5

pppery

.25

ASCII-only

gl everyonbe

Lyxal

04:59

i have my chalk ready

im having great lag right now

HyperNeutrino

same what the hell

i can't load p2

okay GG i'm literally unable to view the problem anymore

ASCII-only

rank 36 part 1

pppery

Same

I got 37 on part 1

HyperNeutrino

17

unless everyone's also getting issues i probably lose p2

looks like CRT to me, maybe?

ASCII-only

diophantine?

im stuck too

HyperNeutrino

05:06

chinese remainder

idk tho

pppery

Only 1 person has done part 2 so far

Now 3 people

Unrelated String

mmm

definitely a bit slow to brute force lmao

pppery

"surely the actual earliest timestamp will be larger than 100000000000000"

ASCII-only

crt sounds like it may work

brute force for each number

Unrelated String

okay yeah it's crt

Redwolf Programs

05:15

I don't know crt :(

Unrelated String

same here

ASCII-only

i didnt either

but i google

also not reall crt it just 1 by 1 brute force

Lyxal

Mine is 100% larger than 100000177492586

Unrelated String

how have 299 people already done this

ASCII-only

im just dumb thats how

idk whats wrong wiyh my thing

HyperNeutrino

05:26

rank 361

pain

if only i actually thought about it for longer instead of switching between my three ideas and messing them all up lol

Redwolf Programs

Wait, am I wrong in assuming a number n's n mod a and n mod b don't change when you add a number made by the product of the factors of n?

Unrelated String

that's sort of what i've been trying to do

but that's probably still way too slow

Redwolf Programs

Mine finished super quick but was wrong

Unrelated String

rip

Redwolf Programs

About a tenth of the minimum it said

Unrelated String

05:28

lol

Lyxal

okay so how do i use this "crt" (Chinese remainder theorem?)

Redwolf Programs

No idea

If someone could explain that'd be really helpful

Unrelated String

wikipedia is not being helpful on how to actually use these bézout coefficients

ASCII-only

ok so

i lied it isnt really crt

tldr do it for 1 thing

now your step is bus # 1

after next? step is bus # 1 * bus # 2

so much spoilers tho so

bye

Unrelated String

okay so it's what me and redwolf are trying lmao

ASCII-only

05:31

im angery btw my thing is erroring for my thing

Redwolf Programs

My theory is right but my implementation is wrong. Go figure. :p

ASCII-only

dumb error

rank 556

pppery

I was able to understand how to do it by reading Wikipedia

Lyxal

okay so if i've understood correctly: find the earliest timestamp for bus 1, find the earliest timestamp for bus 2 starting at the last stamp, then same for the third etc?

or have i missed the mark completely

HyperNeutrino

yeah it's... not actually chinese remainder theorem really

@Lyxal well basically you have a bunch of congruence relations

for example with the sample input, you need to find x such that

x is 0 mod 7
x is 1 mod 13
x is 4 mod 59
...

if you have a value that's 0 mod 7 and 1 mod 13, adding multiples of 7*13 will not change the result

Lyxal

05:33

wdym by "x is y mod z"? you mean x = y mod z?

HyperNeutrino

yeah

ASCII-only

wow i choked hard part 2

oh well

Lyxal

so for the first x, it is a multiple of 7

ASCII-only

wow smh hyper

HyperNeutrino

so you start at 0, which meets the first requirement, then you keep adding 7 until you meet the second requirement (the number is 14), then keep adding 91 until you meet the third requirement, then add 5369, etc

ASCII-only

05:34

spoilers

Lyxal

oh

okay

ASCII-only

hyper what rank did u get btw

HyperNeutrino

sorry it's well past R100 otherwise i wouldn't say anything

ASCII-only

probs 10th tbh

welp

HyperNeutrino

17/361...

ASCII-only

05:35

at least u didnt choke as bad as me...

36/556 :^)

HyperNeutrino

okay i completely screwed up my approach for p2

and my p1 was pretty slow today

ASCII-only

i didnt know how to do part 2 until i did it

also like 3 bugs in p2 as is usual for me

Unrelated String

wait that was easy as hell

i'm just embarrassed now

698 lol

Redwolf Programs

I don't know why I'm wrong

How do you deal with ones where the offset is larger than the number being multiplied?

HyperNeutrino

i think i may have overkilled it

Unrelated String

05:37

your residue checking might be backwards like mine was

HyperNeutrino

anyone else use modinv

ASCII-only

no

Redwolf Programs

I'm doing current_number % bus_number == bus_offset % bus_number, is that correct?

ASCII-only

bro i used js bro

Unrelated String

@RedwolfPrograms that's backwards

Redwolf Programs

05:39

What's backwards?

Unrelated String

you're finding a timestamp where they departed that long ago with that

ASCII-only

@RedwolfPrograms almost. im dumb so i forgot only python (?) keeps positive mod?

tldr

HyperNeutrino

holy shit i'm stupid

ASCII-only

bus_offset is wrong

lel hyper

Unrelated String

you want to add the index and check for divisibility

HyperNeutrino

05:40

oh god i choked on this prob SO hard

i could've gotten it in like sub 10m probably

Unrelated String

unless you can check for congruence with negative numbers lmao

HyperNeutrino

by literally adding two more characters

i hate myself

Unrelated String

@HyperNeutrino saaaaaame

i just spent too long between approaches

i couldn't decide how to try

ASCII-only

two more wtf

Redwolf Programs

I don't get what you're saying, @UnrelatedString

ASCII-only

05:41

funny thing

i got the reduce down waaaay early

just had no idea what to put in it

Unrelated String

@RedwolfPrograms add the offset to the id and check the result against 0

HyperNeutrino

i was checking s % m == r without noting that r could be >= m.........

Redwolf Programs

Id?

Unrelated String

the bus id

HyperNeutrino

s = current, m = bus id, r = offset

Redwolf Programs

05:42

@HyperNeutrino How'd you solve it?

Same issue I have

Unrelated String

when i said add to the id i meant add to the timestamp and not the id

ASCII-only

@HyperNeutrino same

Unrelated String

i got that

HyperNeutrino

@RedwolfPrograms the same brute-force method but using modinv to calculate the required additions because i thought my original method is too slow, but it's just cuz i set a while loop with an impossible fail cond

ASCII-only

spent like 10 mins console logging

Redwolf Programs

05:44

@UnrelatedString So (current_number + bus_offset) % bus_number == 0?

Unrelated String

lol

@RedwolfPrograms yes

HyperNeutrino

oh yeah my answer was negative what it should've been so i just subtracted it from the product of all of the IDs lol

Lyxal

@HyperNeutrino where do i get the 91 from?

ASCII-only

7 * 13

from example

Redwolf Programs

@UnrelatedString Not working still :/

HyperNeutrino

05:46

send your entire sol?

Redwolf Programs

Good luck reading it, but here

ASCII-only

who else has finished btw

HyperNeutrino

how do i interpret this

*run

Unrelated String

@RedwolfPrograms try using LCM instead of just a product perhaps? shouldn't help if the result is still too small

Redwolf Programs

I just verified it and I think it's right, why isn't AoC taking it?

ASCII-only

05:48

not needed

@RedwolfPrograms what's ur input

Unrelated String

check the examples, see if it's too large or too small

ASCII-only

& output

Redwolf Programs

Wait, I bet it's the LCM thing

ASCII-only

shouldn't be

Redwolf Programs

Can I see one of y'alls as an example?

I think I made a typo somewhere

Unrelated String

05:49

no

unless you mean input

ASCII-only

otherwise init wn wp to 0n 1n and wrap wp *= BigInteger(n[0])

HyperNeutrino

aren't they all prime

Rahul Verma

I'm using a while, and I guess it's wrong. I'm checking (req - idx) % val == 0

Redwolf Programs

ohhhhh

Unrelated String

oh yeah its probably a javascript integer precision thing lmao

HyperNeutrino

05:50

oh lmao

ASCII-only

well

HyperNeutrino

well gg

ASCII-only

js has 52 bits precision

Unrelated String

@RahulVerma should be a plus and not a minus

ASCII-only

so like 17 digits

works fine till 1 quadrillion

Redwolf Programs

05:51

Nope, not int precision

HyperNeutrino

huh that should be enough then

Unrelated String

weird

Rahul Verma

@UnrelatedString hm, actually I've written +, that's typo. But, it's not finishing yet

Unrelated String

so yeah maybe your input's indices aren't prime

ASCII-only

my solns are in my hackmd as usual

no cheating tho

Unrelated String

05:51

@RahulVerma huh

ASCII-only

hmmmm

Unrelated String

my solutions are on github to be dug up at leisure

ASCII-only

indices don't matter the bus numbers do. but afaict they're all prime for convenience

if product is odd, the chance they're all prime is veryhigh

Lyxal

@HyperNeutrino is there a way to speed up the algorithm described by your approach?

Unrelated String

i've also taken the incredibly lazy approach to boilerplate of just making my file for the next day as a copy of my current file before i start writing the solution itself

HyperNeutrino

05:52

@Lyxal you can use modular inverse to shortcut it

Redwolf Programs

I miscounted the freaking offsets

Unrelated String

yeah the numbers and not the indices

HyperNeutrino

basically you start at A and add B until it's congruent to C mod D

Unrelated String

i am getting those mixed up so much holy shit

ASCII-only

@RedwolfPrograms i feel like maybe wn + n[1] might work idk tho

HyperNeutrino

05:53

so you can just take (C-A), multiply by the modular inverse of B mod D, and that's the number of times you need to add B

wait my rank actually improved today?

Redwolf Programs

I think I messed up my offsets. I messed up the input parsing.

ASCII-only

well

HyperNeutrino

i dropped to 34th yesterday cuz i choked rly hard on p1

ASCII-only

@RedwolfPrograms maybe. i didn't do that and just did arr.map((element, index)=>element&&[element, index])

Redwolf Programs

Okay it's still wrong

ASCII-only

05:57

wn + n[1] also not it?

wait

ignore me

Redwolf Programs

It should be - n[1]

At least for what I'm doing

Lyxal

@HyperNeutrino what's A, B, C and D in this situation?

ASCII-only

@Lyxal ~~A = index of line. B = line number. C = current. D = current lcm (product since bus lines are all prime)~~

HyperNeutrino

A is your current working value, B is the product of your previous moduli (the value to add so that it doesn't break your working value), C is the offset of the next bus, D is the next bus index / modulus

ASCII-only

yea that

Unrelated String

06:02

...you know, I find it funny that with how the global leaderboard works, we have two people on the private leaderboard between two people who are on the global leaderboard, who are not on the global leaderboard themselves

ASCII-only

:( im sorry im 80 points short of leaderboard

Redwolf Programs

I validated my answer. it is correct. WHY WON'T AoC take it?

ASCII-only

@RedwolfPrograms input pls

and output

HyperNeutrino

wait ascii you're somebody1234 right

ASCII-only

so i can validate

yes

HyperNeutrino

06:04

you're beating me locally?

nice :D

ASCII-only

probs

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along with manish

ASCII-only

also

>:( its cuz i started like 7 and 12 mins late on 2 days

HyperNeutrino

oof

ASCII-only

smh my head. also on mobiel for one day

Redwolf Programs

06:04

Input: gist.github.com/RedwolfPrograms/…

HyperNeutrino

i didn't do day 1 or 7 on that day

and i started day 2 and 3 like 20 minutes late

Unrelated String

@RedwolfPrograms i'm getting something that starts with a 5

Redwolf Programs

Oh, I am...not

HyperNeutrino

same (as unrelated string)

Redwolf Programs

Let me reread the challenge

Unrelated String

06:06

i could compare the sizes of our results

ASCII-only

@UnrelatedString same

Unrelated String

but don't know how to run your code lmao

ASCII-only

5xxxxxx5xxxxxx8

Redwolf Programs

Stupid ten minute delay...I have the right answer but need to wait six minutes :(

ASCII-only

theres ur answer

Unrelated String

06:07

:(

HyperNeutrino

rip

ASCII-only

f

Unrelated String

honestly it might not cost you even one rank lol

at the pace this is going

Redwolf Programs

Top 150 in part one and probably top 150k in part two :p

Unrelated String

never mind it already cost you two ranks

ASCII-only

06:08

lel 1720 finished part 2

Unrelated String

*10

ASCII-only

a hour in. a lot worse than 5k

Unrelated String

and another 10

Redwolf Programs

Apparently y'all were right about something and I thought I had it implemented differently so it was reversed and it...wasn't

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riiiip

Redwolf Programs

06:10

I had tried it earlier and was like "yeah, they're wrong, it still doesn't work", but my input parsing was still incorrect

ASCII-only

the unshift?

Unrelated String

what the hell is an unshift by the way

Redwolf Programs

Yeah I don't know how I managed to forget indexes existed

ASCII-only

anti pop

Unrelated String

wouldn't unshifting just be
shifting in the other direction

ASCII-only

06:10

hahah big rip

Unrelated String

ah

ASCII-only

that is correct

Redwolf Programs

It pushes into the beginning of the array

Unrelated String

so... push

ASCII-only

er yea

Redwolf Programs

06:11

Push is the end of the array

Unrelated String

but to beginning explicitly

ASCII-only

its front push my bad. shift is front pop

btw @HyperNeutrino so... it is crt

Redwolf Programs

Only one more minute to wait

ASCII-only

good luck

let's hope it's not wrong

Redwolf Programs

I checked it against your result with my input, and it matched. I don't see how it could be wrong :p

Unless you're all conspiring to massively troll me, which probably isn't it

HyperNeutrino

06:13

yeah it is CRT i'm just having some difficulty using my brain cells rn lol

Redwolf Programs

Yay, it worked!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Unrelated String

let's go

Redwolf Programs

Took me over an hour but still better than day 7 :p

Unrelated String

:p

Redwolf Programs

Day       Time  Rank  Score       Time  Rank  Score
 13   00:04:25   104      0   01:13:35  1909      0

So close to top 100 in p1

ASCII-only

06:14

what was day 7

hey i was close to top 100 too

Redwolf Programs

The bags one

HyperNeutrino

oh that problem was kinda annoying

Unrelated String

i can't believe i've still only hit top 100 once this year

HyperNeutrino

especially when i kept typing clear gold as the root instead of shiny gold...

Redwolf Programs

rip

Unrelated String

06:15

i think today was the closest i've gotten since i did actually get top 100 on day 2 lol

Lyxal

@HyperNeutrino have i understood things correctly?

HyperNeutrino

recursive invmod monkaw

ASCII-only

i didnt do to shabby on day 7 surprisingly

HyperNeutrino

that looks right

Lyxal

@HyperNeutrino i found the function here

HyperNeutrino

06:18

lmao, nice

Lyxal

@HyperNeutrino well it isn't.

HyperNeutrino

oh :(

Lyxal

it outputs 6176089 for the sample

HyperNeutrino

haven't run / debugged it yet

i can take a look

ASCII-only

are invmod args in the right order

HyperNeutrino

06:20

yes

ASCII-only

yea ignore me

i feel like the bit thats being added dont look right. (jk)

HyperNeutrino

why is it outputting 7 for the input

am i running it wrong

ASCII-only

also ew lyxal don't for in len range

if for in array can do the trick

Lyxal

I updated the gist: gist.github.com/Lyxal/7d419c2c5a95f2c26a7a0f2f09ca2337

@ASCII-only as i said yesterday: once an hour passes, I don't care about elegance i only care about getting it working

HyperNeutrino

wait what are these values

Lyxal

06:29

at this point i honesly dont know. what exactly is the offset of the next bus?

HyperNeutrino

the offset is the index, the modulus is the bus ID

okay so i fixed your solution by changing 0 to 1 in your outer for loop

because the invmod shortcut breaks when the existing value is already valid, i suppose

also the resulting value is -1x what the value should be (it's positive, but you can just do -n % m)

idk why or how to fix it smartly, but just do brute force lol

it's O(N max M) times the "smart" modinv sol, which is tiny

Lyxal

methinks i better try this again tomorrow

because right now, i have no clue what tf Im doing

HyperNeutrino

fair enough

lol

Anush

12:09

hello!

New Main Posts

12:20

0

Q: Iterate over the neighborhood of a string

Input A string S of length between 2 and 20. The only letters in the string will be a or b. Output All strings within Levenshtein distance 2 of S. You must output all the strings without duplicates but in any order you like. Example If S = aaa then the output would be (in any order) a aa ab ba aa...

code-golf

Wheat Wizard

14:05

@xash Is it possible to make a ' character in convey? I can't seem to put it in a string for obvious reasons, and doing math with characters seems to convert them permanently to numbers.

Razetime

14:41

started way too late lol

pppery

I started on time, but then, after struggling for half an hour, gave up and went to bed. After waking up, I was able to finish in 5 miniutes

Razetime

I'm starting now lmao

just finished p1

pppery

P2 is much harder

Redwolf Programs

I don't even remember what p1 was about, lol

pppery

Which bus to actually ride

It makes much more sense than part 2, which is a random math challenge devoid of any real connection to the story

Redwolf Programs

14:52

agreed

Razetime

15:08

@pppery hm yeah very large number

pppery

My answer was around 210 trillion

Razetime

holy moly

maybe I should start at a huge number

Wheat Wizard

15:23

@xash Also .s seem to be very broken.

Razetime

15:39

@pppery ok now I'm starting to understand why you said this

xash

@WheatWizard '…\'…' escapes now correctly. You mean the whole f. thing?

Wheat Wizard

Yeah, sometimes . is applied to the character after it, or above it.

Maybe I just don't understand.

Razetime

hello everyone

Wheat Wizard

@xash For example this program https://λ.land/convey/run.html#eyJjIjoiPj4+dlxuXiAgdlxuLC4tLFxuWyAwWyIsInYiOjEsImkiOiIifQ==

xash

I took the easy route when implementing it: first all functions are parsed, with . being a 1-1 function. Then, whenever a function has a . in its output, it is applied to it. So {f.} and }.f{ are the same.

Wheat Wizard

15:48

Ok, that is very confusing.

xash

It is kinda helpful for this case: https://λ.land/convey/run.html#eyJjIjoiICAgfVxuey8rP1xuIHYuXlxuID4sXiIsInYiOjEsImkiOiIxIDEzIDYgOCJ9

For it to be so simple, +. would have then be one function taking two tiles, so that ? still sees the left as empty … maybe there is a cleaner solution.

Another downside to its non-intuitiveness is that f and f. always need to have the same number of in- and output ports.

Wheat Wizard

Oh and I think & is still broken

https://λ.land/convey/run.html#eyJjIjoiez5cInYgICAxXG4gIDA9diY+QCRgdlxudjw8PDxeICs/LDxcbj4+Pj52XiBcIjBeXG4gICAgPl4gfSIsInYiOjEsImkiOiIxIDIgMSAyIDEgMiAxIDEgMSAxIDIgMSAyIDEgMiAxIDEgMSAyIDEgMiJ9

If you remove the queue from this it changes the output. It looks like some things are getting lost in the queue.

xash

16:13

@WheatWizard I missed a ! in my fix yesterday. Sorry for that. Works now … uh, better at least.

Wheat Wizard

No problem for me, thanks for fixing it.

New Main Posts

21:09

1

Q: Can you make your way through the Ulam spiral?

You will be given a point (x,y) relative to the center of the Ulam spiral (the point which represents one), and length z. The task is to check whether there exists a path from (0,0) to (x,y) of length z, assuming prime numbers are obstacles and each turn in path has an angle of 90 degrees. Path m...

code-golf decision-problem

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