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4:00 PM
Didn't we already have a PPCG challenge on that puzzle?
 
@CᴏɴᴏʀO'Bʀɪᴇɴ I didn't write it out. But, for the 3x3 at least, I know a sequence to toggle each individual light, so combining those for the result you want gets you there.
 
@CᴏɴᴏʀO'Bʀɪᴇɴ What's the original question?
 
I'm on mobile rn and can't link ya
@mbomb007 Oh, interesting! I'll work on a generic sequence for lights. It shouldn't be that hard, for say if two patterns toggle lights A0...AN and B0...Bm, then applying both patterns gives a pattern that toggles the states of the symmetric difference, leaving the intersection untouched
 
@CᴏɴᴏʀO'Bʀɪᴇɴ It might not work on 4x4, bc that's different. I'll post the sequences for 3x3 though. Rotational symmetry makes it quick.
 
@trichoplax I'm looking at Netfirms and Namesilo right now.
I'm kinda skeptical of Netfirms (like, what does the $1.99 price mean?)
 
4:10 PM
Corner: [[0,2],[2,0],[0,0],[1,1]]
Edge: [[1,2],[1,0],[0,1],[0,2],[0,0],[1,1]]
Center: [[0,0],[1,0],[2,0],[0,1],[1,1],[2,1],[0,2],[1,2],[2,2]]
 
@PhiNotPi I now understand that I understand less than I thought I did
 
That ping should of actually been directed to @zyabin101, since he was the person who originally posted those prices.
 
Do you mean toggling the lone square in the center of a 3x3?
 
@El'endiaStarman Yeah.
 
4:11 PM
You can do it in 9. Click all the squares. :P
 
Is the puzzle being discussed the lights out puzzle? We have various challenges inspired by it here, here, here and here (not necessarily making this a duplicate)
 
relink the thingy?
the jsfiddle
 
@PhiNotPi $1.99 is the registration price for the domain.
 
@EᴀsᴛᴇʀʟʏIʀᴋ thingy
 
4:16 PM
thankee
took 4 moves.
Can it be solved in less than that?
 
Any position can be reached in n*m moves where n by m is the board dimensions, assuming that the given configuration is possible.
 
@mbomb007 So I can finally solve the board in 25 moves! \o/
 
@trichoplax They're all similar, but my lights out game also toggles the diagonally adjacent tiles, whereas none of those do.
 
you can also solve it in less.
 
@EᴀsᴛᴇʀʟʏIʀᴋ Not necessarily.
 
4:21 PM
How much did it took for you?
 
@zyabin101 I found this on their site: Domain .com, .net and .org sale pricing is $9.95/year for the first year. Domain will renew at $12.49 each year thereafter.
 
O_o
 
Use internet.bs already :P
 
@EᴀsᴛᴇʀʟʏIʀᴋ If the starting configuration on a 3x3 is only the center tile, then solving it takes 3*3 = 9 moves.
 
@mbomb007 for this specific configuration (blank to full), it takes 4 moves for a 5*5 board.
 
4:23 PM
@PhiNotPi Well, actually, the $1.95 price was the price on the Add button. D:
 
@EᴀsᴛᴇʀʟʏIʀᴋ That's not the puzzle, though. That's trivial on any board size.
 
@mınxomaτ The Internet is all BS
 
@mbomb007 okay
 
The challenge is to get to blank from any starting configuration.
 
I modded the JS fiddle to cycle between three colors. It's weirdly kinda more interesting and kinda less interesting.
 
4:27 PM
@El'endiaStarman Share the fiddle?
I could try to make four colors! It will be very hard.
(To solve)
 
Four colors is probably fairly uninteresting.
 
D:
 
@El'endiaStarman Use this one instead: jsfiddle.net/4o7vekpe/1
It has the added functionality by @CᴏɴᴏʀO'Bʀɪᴇɴ for automated moves given an input list.
 
Ooh, okay.
 
4:30 PM
And it tracks your moves.
Then, if you want the simplified move set to get from an empty board to where you are, simply sort the moves, then remove pairs of duplicates.
 
How to play the game?
 
@BaldBantha It's less a game and more just for fun.
Normally, there'd be a random starting position, and you'd need to get to a blank board.
 
what I figured when I saw the symetrical patterns and stuff. There should be a bigger board
 
@BaldBantha Make it bigger.
Change the number and click "Update"
 
Okay, I made the edit. Hmm. I should've forked it, hmm?
 
4:33 PM
Max is 20.
@El'endiaStarman Yeah, fork it.
 
You forgot the blank one.
 
@mbomb007 Incidentally, this doesn't apply when you have 3 colors. You'd remove groups of three of the same. So basically, mod n, where n is the number of colors.
 
@El'endiaStarman Yeah, I know.
Every configuration is still possible on a 3x3, I believe.
 
Yeah. You just have to repeat a sequence to toggle one square between the three colors.
 
4:39 PM
@El'endiaStarman Try to get only the center.
 
0
Q: Algorithm to generate mountain ranges with upstrokes and down-strokes (java)

salamanka44I tried to do the classical problem to implement an algorithm to print all valid combinations of n pairs of parentheses. And I found this program (which works perfectly) : public static void addParen(ArrayList<String> list, int leftRem, int rightRem, char[] str, int count) { if (leftRem < 0 ...

 
...oh, hrm.
I got center magenta with [[2,2],[1,1],[0,0],[1,1],[0,2],[1,1],[2,0],[1,1],[0,0],[1,1],[2,2],[1,1],[0,2],‌​[1,1],[2,0],[1,1],[1,0],[1,1],[1,2],[1,1],[0,1],[1,1],[2,1]].
Need to remove groups of 3.
 
What's the pros/cons of whois privacy?
 
@PhiNotPi If you're ever a mod, get it.
cuz people will look you up, find your phone number, and call you to yell at you for suspending them
 
@PhiNotPi Information about you is hidden in the site's WHOIS response.
 
4:48 PM
@El'endiaStarman ...why can't I paste this into Python? I'm getting SyntaxError: invalid character in identifier. Weird.
 
does internet.bs have whois privacy?
 
idk
 
@CᴏɴᴏʀO'Bʀɪᴇɴ @El'endiaStarman On a 4x4, every configuration is possible:
Corner: [[0,0], [0,2], [0,3], [2,0], [2,2], [2,3], [3,0], [3,2], [3,3]]
Edge: [[2,0], [3,0], [2,2], [3,2], [2,3], [3,3]]
Inside: [[2,2],[2,3],[3,2],[3,3]]
 
@MartinBüttner sorry for late reply
 
But 1&1 includes one for free.
 
4:50 PM
but I don't feel that embedding in a higher dimensional space adds power
 
@ArtOfCode If someone does that, file charges with the FBI (or equivalent) for threats and harrassment
 
ohai ~rys
 
since you can map Z^3 <-> Z
 
As an email administrator, having privacy WHOIS really hurts troubleshooting.
 
@TimmyD in theory that would be great. The reality is that they don't care.
It's happened to enough mods around here.
 
4:51 PM
> A user buys privacy from the company, who in turn replaces the user's info in the WHOIS with the info of a forwarding service (for email and sometimes postal mail, done by a proxy server).
 
I have an interesting chat challenge
 
Domain privacy is a service offered by a number of domain name registrars. A user buys privacy from the company, who in turn replaces the user's info in the WHOIS with the info of a forwarding service (for email and sometimes postal mail, done by a proxy server). == Level of anonymity == Personal information is typically collected by these registrars to provide the service. Some registrars take little persuasion to release so-called 'private' information to the world, requiring only a phone request or cease and desist letter. Others, however, treat privacy more seriously, and host domain names...
@orlp I have an interesting chat solution
 
maybe for @MartinBüttner @Dennis @Sp3000 @trichoplax
 
Or not.
 
@mbomb007 wow, interesting
 
4:52 PM
let's say I have a n 32-bit numbers with no discernible compression pattern
if I want to store them, normally I have to spend 32*n bits
but what if I don't care about their order?
 
>>> s = "[[2,2],[1,1],[0,0],[1,1],[0,2],[1,1],[2,0],[1,1],[0,0],[1,1],[2,2],[1,1],[0,2],‌​[1,1],[2,0],[1,1],[1,0],[1,1],[1,2],[1,1],[0,1],[1,1],[2,1]]"
>>> len(s)
141
>>> sum(s.count(c) for c in '[],012')
139
>>> list(map(ord,s))
[91, 91, 50, 44, 50, 93, 44, 91, 49, 44, 49, 93, 44, 91, 48, 44, 48, 93, 44, 91, 49, 44, 49, 93, 44, 91, 48, 44, 50, 93, 44, 91, 49, 44, 49, 93, 44, 91, 50, 44, 48, 93, 44, 91, 49, 44, 49, 93, 44, 91, 48, 44, 48, 93, 44, 91, 49, 44, 49, 93, 44, 91, 50, 44, 50, 93, 44, 91, 49, 44, 49, 93, 44, 91, 48, 44, 50, 93, 44, 8204, 8203, 91, 49, 44, 49, 93, 44, 91, 50, 44, 48
Well, there's my problem: those 8204 and 8203 in the middle of the string.
 
there are n! ways to shuffle them, that are all equal
 
But what are those?!
 
@PhiNotPi the answer is yes
 
so for 100 elements, there's 100! different representations of a single element, wasting log2(100!) = 524 / 3200 bits to encode that
that's almost 16%!
 
4:55 PM
@ArtOfCode Wait, really? I'd always figured that was some sort of urban legend ... I didn't realize that people actually took time to do that.
 
@TimmyD people are terrible
 
People need more zen.
 
And more Jesus.
> Y'all need more Jesus!
 
hoooooooooooooly crap
I just realized something
log2(n!) ~ n log n
 
@orlp it does, because the projection at the end can create cycles even if g doesn't have any.
 
4:56 PM
@El'endiaStarman No idea.
Why are you trying to do that anyway?
 
@ArtOfCode I wonder if it's worth digging up some of the mod-related emails I've gotten.
 
so if you store n copies of some fixed amount of bits without something to ignore ordering, you will use 100% of your storage to store only order, for big enough n
 
@El'endiaStarman In Unicode, 8203 is a zero width space and 8204 is a zero width non-joiner. Has to do with the line break in the JSfiddle.
 
Actually, I'm not going to do that.
 
since n log n is asymptotically bigger than n
@MartinBüttner you mean projection I hope?
 
4:57 PM
@mbomb007 Was gonna use Python to toss out duplicates.
 
@MartinBüttner either way, f can already do that
 
@PhiNotPi what for?
 
@orlp ummm...
 
consider f(x) = g(x) = f^-1(x) = x XOR 1
 
1 min ago, by PhiNotPi
Actually, I'm not going to do that.
 
4:58 PM
@orlp how is that?
 
f-1(g(f(1))) = 0
 
@orlp then g itself already has a 2-cycle
 
f-1(g(f(0))) = 1
 
If g doesn't then f-1 g f won't either
 
Okay, @mbomb007, with three colors, center magenta is [[0, 0], [0, 0], [0, 1], [0, 2], [0, 2], [1, 0], [1, 1], [1, 1], [1, 2], [2, 0], [2, 0], [2, 1], [2, 2], [2, 2]].
 
5:01 PM
@mınxomaτ I'm looking into that.
Is it a bad idea to log in with (one of) my gmail accounts?
 
Accordingly, yellow center is [[0, 0], [0, 1], [0, 1], [0, 2], [1, 0], [1, 0], [1, 1], [1, 2], [1, 2], [2, 0], [2, 1], [2, 1], [2, 2]].
 
I kinda lost the two color fiddle... Link me again?
[[0,0],[2,2],[3,3],[1,1],[4,4]] makes a beautiful pattern.
 
34 mins ago, by mbomb007
@El'endiaStarman Use this one instead: https://jsfiddle.net/4o7vekpe/1/
 
@El'endiaStarman Danke sch'o'n.
 
@MartinBüttner I'm not convinced yet but I have to do more thinking
 
5:07 PM
Tapping all squares in this order:
[[0,0],[1,0],[2,0],[3,0],[4,0],[0,1],[1,1],[2,1],[3,1],[4,1],[0,2],[1,2],[2,2],[‌​3,2],[4,2],[0,3],[1,3],[2,3],[3,3],[4,3],[0,4],[1,4],[2,4],[3,4],[4,4]]
Makes a square in the middle.
 
It actually doesn't matter what order you tap them.
 
Adobe actually called their new software "Xd"...
 
Does that mean it's dead on arrival?
 
Welp, actually, [[2,2]] makes the same square... :P
I golfed 24 moves out of this moveset.
 
@MartinBüttner I managed to convince myself
 
5:12 PM
@orlp this is what we proved the other day. if h has a 2-cycle then for some x, h(h(x)) = x --> f^-1 g f f^-1 g f (x) = x --> f^-1 g g f (x) = x --> g(g(f(x)) = f(x), so g has a 2-cycle. the deduction also works the other way round which proves that h and g have exactly the same types and numbers of cycles
(sorry, I had already typed it up :P)
 
haha
yeah basically the same logic
the f and f^-1 cancel out in the middle
@MartinBüttner what exactly do you consider a projection?
an arbitrary function Z^3 -> Z?
 
yeah, pretty much, although I can't choose it freely. let's say it's just p(x,y,z) = x
 
what is this for btw?
 
it may or may not be for some future esolang :P
 
5:19 PM
   (3&,$(],log2f,nlogn)@i.)11
0 1       2       3       4       5       6       7       8       9      10
0 0       1 2.58496 4.58496 6.90689 9.49185 12.2992 15.2992 18.4691 21.7911
0 0 1.38629 3.29584 5.54518 8.04719 10.7506 13.6214 16.6355  19.775 23.0259
(table of n, log_2 n!, and n log n)
 
maybe this is an interesting challenge?
write a compressor/decompressor that uses the least amount of bits on average to store randomly generated sets of 64-bit integers
whoever uses the least bits on average wins
 
Uh, isn't that just 64 bits?
 
@RenderSettings no, randomly generated sets of 64-bit integers
 
Can't reduce n bits of entropy below n bits. If you took the average for all 64 bit numbers "compressed" then it's either at or above 64.
 
5:28 PM
@RenderSettings the crux is the set
the numbers are unordered
 
if you store 1000 64-bit numbers the usual way it's 64000 bits
 
Hardcode the list of numbers you are being tested on, reduce them into the index into the list.
 
randomly generated
the test program will use random generation
and besides, that's a standard loophole
but log2(1000!) / 64000 bits are wasted
which is 13%
 
Ah, ok. I get it.
 
5:30 PM
Wouldn't any savings have to be targeted at the set generated? What general-use compression can you really use for randomly generated integers?
 
@Geobits the crux is that any storage we humans do has order
but the set is unordered
 
To give an idea of how one might approach it
 
@orlp As well as any storage in a computer...
 
@El'endiaStarman I got duplicate removal to work in Python: repl.it/CUK5
Taking a break. Be back in an hour maybe.
 
For two 64-bit integers, you can store them back to back in a 128-bit array. The order doesn't "use up" any bits at all.
 
5:34 PM
@Geobits that's not true
let's say you store 3 and 5
that could also have been 5 and 3
 
Yes. And both take up the same space...
 
there's two possible pairs that encode the same value
that's one wasted bit
(not quite as 5 5 is unique)
 
Where exactly is this wasted bit going then? How could you possibly store them to "save" it?
 
well, that's the challenge
 
Just take out all the 0s from the binary! They're just wasted space!
2
 
5:36 PM
@orlp My premise is that it isn't really possible, though.
 
@Geobits you are definitely wrong
 
I'm willing to change my mind given evidence. I just haven't seen any.
 
well, you can always just enumerate all combinations with replacement
 
3 requires two bits and 5 requires 3 bits. You could store them as 3 2, so long as you know that the numbers after the first are successive differences, and this requires only 4 bits, as opposed to 5.
 
@orlp Challenge complete!
 
5:38 PM
@wizzwizz4 Which challenge?
 
The point is that maybe doing something with 5 3 will be even more efficient. (Not necessarily in this case since its so small.)
 
2 mins ago, by orlp
well, that's the challenge
Ask @orlp.
 
@RenderSettings heh
 
@wizzwizz4 well
this isn't a practical algorithm
 
@orlp Whoever said anything about practical? This is PPCG, after all.
 
5:40 PM
if I give you 1000 64-bit elements, good luck enumerating those combinations
@wizzwizz4 the fact that it's a code-challenge
if your solution isn't practical it doesn't count
 
@orlp I've been waiting for 3 days and 2 nights to post that message here seamlessly into conversation. And it didn't work. :-(
 
@J users: is there a better way to write (y f n) g y tacitly than ] g~ n f~ ]?
 
@CᴏɴᴏʀO'Bʀɪᴇɴ Try naming specific J users. It might work -
Hmm...
 
@Geobits Easiest way for 2 numbers is to enumerate (0,0) -> 0, (0,1) -> 1, (1,1) -> 2, (0,2) -> 3, etc., i.e. f=lambda n,m:n*(n+3)/2+m where n >= m. Then you can store the two numbers in a smidgen over 127 bits (recovery's a bit tricky, but for sufficiently large n you can do g=lambda k:int((2*k)**.5-1))
 
Maybe we should add groups to chat!
 
5:49 PM
@wizzwizz4 I was thinking that
I could make a user script
 
I could make a meta post, then link your user script.
Ooh, I know! Add it to ZyabinVI! @zyabin101
 
How would a group ping work? {name}?
 
@CᴏɴᴏʀO'Bʀɪᴇɴ @@name?
 
@@wizzwizz4
Did that ping you?
 
... Ok, we'll go with yours.
 
5:52 PM
Maybe @{name}
a combination of both worlds
 
@Sp3000 now n numbers :)
or at least at 3 you'll save your first full bit
 
0
A: Sandbox for Proposed Challenges

weatherman115Primary Chances Write a program that lists all possible outcomes for a general election with any number of candidates. Rules: Your answer must output how many states each candidate won in any format. Candidates can have any name. This is code-golf, so standard loopholes are forbidden, and s...

 
Hmm I think I got my formula a tad wrong. Close enough though, point still stands.
Eh, ceebs enumerating :P
I'm sure there's a usable formula for the encoding part, but backwards is a bit trickier
 
oh
then you're only halfway there
 
@wizzwizz4 Nope. zyabinVI is not a hosting for projects, it's an experimenting organization.
 
5:53 PM
the challenge is to write an algorithm that goes back and forth :P
 
I never said I was going to do your challenge :P
 
@zyabin101 Good point. :blush:
 
@Sp3000 well, you can't stop now
 
Oops, too much GitHub.
 
@zyabin101 why zyabin 6 if you're zyabin 5?
 
5:55 PM
@orlp I'm zyabin101.
 
...
 
I randomly chose zyabinVI, from some roman numbers I know. :P
 
Read the starboard, top to bottom.
 
for anyone that plays hearthstone
the biggest salt there is
 
f=lambda n,m:n*(n+3)//2-m sign error :P
 
6:01 PM
@Sp3000 Oh god, that's gotta be the least practical idea ever for a set of 1000 integers :P
I guess it does work, though, for not very much savings.
 
I've got a method:
Work out which PRNG is being used, then output only the numbers you needed to work that out and calculate the others.
i.e., hope it's the Mersenne Twister :-)
 
>_>
18
A: 4, 8, 15, 16, 23, 42

GeobitsJava I can't find a pattern in that sequence. If there's no recognizable pattern, we might as well just throw a bunch of small primes together, cram them into Java's built-in RNG, and call it a day. I don't see how that could possibly go wrong, but then again, I'm an optimist :) import java.uti...

 
@Geobits Yeah well, ~2! doesn't really help much :P
Hmm decoding might not be too bad with a bit of binary searching
 
6:17 PM
@orlp Woo! I got put in a category with @MartinBüttner, @Dennis and @Sp3000!
@orlp That reminds me of this solution to tweet image compression - it used the permutation of the regions it stored in order to encode extra information
 
@orlp Yeah actually I think going both ways isn't too bad. The number of sets of k numbers where the largest number is n is just binomial(n,k) and you can use that recursively for encoding similarly to the two-number case. And I think you can binary search the reverse way
 
@MartinBüttner what is your PhD about btw?
 
@orlp Memory efficient source code.
 
@flawr I wish...
@orlp I'm in a group for computer graphics and visualisation. Most of the research here is about uncertainty/ensemble visualisation.
 
anyone know how to play the ping noise for stack exchange?
 
@CᴏɴᴏʀO'Bʀɪᴇɴ Like this?
 
@CᴏɴᴏʀO'Bʀɪᴇɴ With what?
 
yes, but programmatically
 
6:38 PM
@MartinBüttner if I understand you correctly, this is less in the direction of SIGGRAPH, but more in the direction of human-computer interaction and psychology?
 
I don't even know that sound, can someoneping me?
 
@orlp more in the direction of IEEE VIS if you want to compare it to SIGGRAPH :P
 
@Bálint It's this
 
@Bálint ping
 
@Bálint ping
 
6:38 PM
@Bálint ping
 
some people in the group are also working on more SIGGRAPH'y stuff though ;)
 
Ok, enough
@CᴏɴᴏʀO'Bʀɪᴇɴ With wich language do you want to achieve it?
 
@orlp ideone.com/ZW8s4l I think I'll leave the decoder as an exercise, gotta sleep
 
The easiest would be to record it then
 
6:40 PM
I'm writing a userscript/javascript
 
@CᴏɴᴏʀO'Bʀɪᴇɴ Is it in the source of this webpage?
 
Then insert an audio tag in the HTML file, and play it
 
↰@​Bálint ping
 
@trichoplax idk, the source for se is large
 
@aditsu Fail, I already muted down my sound
 
6:41 PM
@Bálint fail, I didn't ping you
 
@CᴏɴᴏʀO'Bʀɪᴇɴ Maybe outsource the tedious searching to SO? Or use a text search?
 
@trichoplax that's a good idea
 
@CᴏɴᴏʀO'Bʀɪᴇɴ Maybe look up "notification" in a thesaurus and search for all the variations
Or just search for whatever JS uses for sound
 
I think SE obfuscated their source code >_>
they aliased playSound twice
 
That's still only 2 to search for...
 
6:45 PM
Someone please ping me
 
@Bálint sure
 
@trichoplax it's a one-letter alias: a.
 
What event does occur, if we set the playing tag on an audio element to "play"?
 
@CᴏɴᴏʀO'Bʀɪᴇɴ Do you know what characters should come immediately before and after it when used?
 
Any ideas?
 
6:46 PM
@trichoplax maybe ( after, but that hardly helps
 
@Bálint I don't know JS sound...
@CᴏɴᴏʀO'Bʀɪᴇɴ Will it always be a space before?
 
@CᴏɴᴏʀO'Bʀɪᴇɴ Found it for you: cdn-chat.sstatic.net/chat/se.mp3
 
Nice :)
 
Hey!
 
Ok, I'm not going to lie, I opened the Chrome elements menu, then I searched for "audio"
 
6:49 PM
It worked...
 
@MartinBüttner well, since that's your area of expertise, what do you think of this graph?
 
@CᴏɴᴏʀO'Bʀɪᴇɴ document.getElementsByTagName("audio")[0].play();
is anyone here familiar with german counting system?
 
@drobilc (n)ein
 
@drobilc We have a couple German speakers in here. :P @MartinBüttner, for one.
 
6:57 PM
And flawr, me, Dennis (sort of) ...
 
@drobilc ein, zwei, drei, vier, fünf, sechs, sieben, acht, neun, zehn, elf, zwölf, dreizehn, vierzehn, fünfzehn, sechszehn, siebzehn, achtzehn, neunzehn, zwanzig, einundzwanzig, etc. (it becomes long from here)
 
quick! the mods are gone! post pictures of cute fluffy kittens
 
@drobilc In wich aspect do you mean? The "say the last numbers in reverse"?
 
@Bálint "say the last numbers in reverse" aspect :)
 
@orlp sorry what
:)
 
6:59 PM
@drobilc What's with it?
 
@Bálint Well, i was wondering if there was a challenge about that :)
 

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