Sandbox for Proposed Challenges

This "sandbox" is a place where Code Golf users can get feedback on prospective challenges they wish to post to main. This is useful because writing a clear and fully specified challenge on your first try can be difficult, and there is a much better chance of your challenge being well received if you post it in the sandbox first.

Sandbox FAQ

Posting

To post to the sandbox, scroll to the bottom of this page and click "Answer This Question". Click "OK" when it asks if you really want to add another answer.

Write your challenge just as you would when actually posting it, though you can optionally add a title at the top. You may also add some notes about specific things you would like to clarify before posting it. Other users will help you improve your challenge by rating and discussing it.

When you think your challenge is ready for the public, go ahead and post it, and replace the post here with a link to the challenge and delete the sandbox post.

Discussion

The purpose of the sandbox is to give and receive feedback on posts. If you want to, feel free to give feedback to any posts you see here. Important things to comment about can include:

• Parts of the challenge you found unclear
• Comments addressing specific points mentioned in the proposal
• Problems that could make the challenge uninteresting or unfit for the site

You don't need any qualifications to review sandbox posts. The target audience of most of these challenges is code golfers like you, so anything you find unclear will probably be unclear to others.

If you think one of your posts requires more feedback, but it's been ignored, you can ask for feedback in The Nineteenth Byte. It's not only allowed, but highly recommended! Be patient and try not to nag people though, you might have to ask multiple times.

It is recommended to leave your posts in the sandbox for at least several days, and until it receives upvotes and any feedback has been addressed.

Other

Search the sandbox / Browse your pending proposals

The sandbox works best if you sort posts by active.

To add an inline tag to a proposal, use shortcut link syntax with a prefix: [tag:king-of-the-hill]. To search for posts with a certain tag, include the name in quotes: "king-of-the-hill".

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Crab Canon

A crab canon is a piece of music where the same tune is played backwards and forwards at the same time, and it somehow sounds nice. The most famous example is this one by Bach. In Godel, Escher, Bach, Douglas Hofstadter wrote a crab canon in dialog form, in which the characters of Achilles and the Tortoise alternate lines, with one set of lines being the same as the other set except backwards. Somehow, it makes sense.

The challenge is to write a program inspired by this art form. The only requirement is that there has to be some sort of reversal of the source code involved. For example, you could make a program that:

• Prints its own source code, but backwards
• Does the same thing when reversed
• Both of the above at the same time
• Or make up something creative and wow the voters!

The reversal can happen on pretty much whatever level you want: lines of code, characters, characters within lines, or whatever makes sense for your language. The Hofstadter Crab Canon has some small changes between the two sets of lines for the sake of coherence, you can do something similar if you feel it is necessary.

This is a popularity contest, the answer with the most votes wins.

• This is without a doubt too broad. See codegolf.stackexchange.com/tags/popularity-contest/info Aug 16, 2016 at 7:10
• @PeterTaylor FYI there's something wrong with that link's formatting Aug 16, 2016 at 18:07
• There isn't any formatting. I just pasted the link directly. And it works for me. Aug 16, 2016 at 19:11
• @PeterTaylor hmm, seems to have fixed itself... Aug 16, 2016 at 19:12

Petals around the Roses

Given 5 numbers from 1 to 6, calculate the number of Roses, Petals and Roots. Try guessing the formulas yourself by visiting http://jetpackshark.com/RPS before reading anybody's answers. (The dice-like display is significant.)

This is , so the shortest program wins.

• If you're looking for a "solve-the-puzzle" challenge, the site for that is Puzzling. If you want it to be a code-golf, then please include a formula for how the roses, petals, and roots are calculated. Aug 16, 2016 at 13:06
• Or at the very list a definition of roses, petals, and roots in this context. At present this question makes no more sense than the output of a Markov text generation process. Aug 16, 2016 at 13:44

Write a Brainfuck interpreter in Brainfuck

Since Brainfuck is known to be turing-complete, it is possible to write a Brainfuck interpreter in Brainfuck. This is what you're supposed to do.

You will get the input from the standard input and output to the standard output. This is a programming-puzzle, so the length is not top priority, however if there are multiple solutions, the shortest one wins!

• BF interpreter (non language specific) challenge has already been done, and language exclusive challenges generally aren't good Aug 19, 2016 at 1:45

Iпtгodцctioп

Iп tиe Iпteгпets, people sometimes liкe to stчlize tиeiг posts дs if tиeч щeгe щгitteп iп д diffeгeпt scгipt. Tидпкs to tиe пotoгietч of Soviet Яцssiд, tиe Cчгчlic scгipt seems to бe pдгticцlдгlч fдvoгed.

Бцt щидt cдп д пext-dooг tгoll do if tиeч'гe пot д pгogгдmmeг? Mдпцдllч гeplдciпg eдcи дпd eveгч letteг cдп бe qцite tedioцs...

Cидlleпge

Чoц дгe to щгite д pгogгдm tидt щill дccept дп дгбitгдгilч loпg iпpцt of Lдtiп cидгдcteгs дпd sцбstitцte some letteгs щitи similдгlч looкiпg Cчгчlics cидгдcteгs. Tиe oцtpцt sиoцld бe ideпticдl to tиe oцtpцt pгodцced бч tиe folloщiпg цпgolfed C# scгipt:

цsiпg Sчstem;
цsiпg Sчstem.Collectioпs.Geпeгic;
цsiпg Sчstem.Liпq;

pцбlic clдss Test
{
pцбlic stдtic void Mдiп()
{
Dictioпдгч<cидг, cидг> tгдпs = пeщ Dictioпдгч<cидг, cидг>{
{'A', 'д'},
{'a', 'д'},
{'B', 'Б'},
{'b', 'б'},
{'N', 'И'},
{'b', 'и'},
{'K', 'К'},
{'k', 'к'},
{'N', 'П'},
{'n', 'п'},
{'R', 'Я'},
{'r', 'г'},
{'U', 'Ц'},
{'u', 'ц'},
{'W', 'Щ'},
{'w', 'щ'},
{'Y', 'Ч'},
{'y', 'ч'}
};

stгiпg s; щиile((s = Coпsole.ЯeдdLiпe()) != пцll) {
Coпsole.ЩгiteLiпe(
пeщ stгiпg(s.Select(c => tгдпs.CoпtдiпsКeч(c) ? tгдпs[c] : c).
Toдггдч()
)
);
}
}
}


Tиe sиoгtest code щiпs.

Exдmple Iпpцt дпd Oцtpцt

Iпpцt:

As we know, the goal of every struggle is victory. But if the proletariat is to achieve victory, all the workers, irrespective of nationality, must be united. Clearly, the demolition of national barriers and close unity between the Russian, Georgian, Armenian, Polish, Jewish and other proletarians is a necessary condition for the victory of the proletariat of all Russia.

We are for the withering away of the state, and at the same time we stand for the strengthening of the dictatorship of the proletariat, which represents the most powerful and mighty of all forms of the state which have existed up to the present day. The highest development of the power of the state, with the object of preparing the conditions of the withering away of the state: that is the Marxist formula. Is it "contradictory"? Yes, it is "contradictory." But this contradiction is a living thing and wholly reflects the Marxist dialectic.

Oцtpцt:

дs щe кпoщ, tиe goдl of eveгч stгцggle is victoгч. Бцt if tиe pгoletдгiдt is to дcиieve victoгч, дll tиe щoгкeгs, iггespective of пдtioпдlitч, mцst бe цпited. Cleдгlч, tиe demolitioп of пдtioпдl бдггieгs дпd close цпitч бetщeeп tиe Яцssiдп, Geoгgiдп, дгmeпiдп, Polisи, Jeщisи дпd otиeг pгoletдгiдпs is д пecessдгч coпditioп foг tиe victoгч of tиe pгoletдгiдt of дll Яцssiд.

Щe дгe foг tиe щitиeгiпg дщдч of tиe stдte, дпd дt tиe sдme time щe stдпd foг tиe stгeпgtиeпiпg of tиe dictдtoгsиip of tиe pгoletдгiдt, щиicи гepгeseпts tиe most poщeгfцl дпd migиtч of дll foгms of tиe stдte щиicи идve existed цp to tиe pгeseпt dдч. Tиe иigиest developmeпt of tиe poщeг of tиe stдte, щitи tиe oбject of pгepдгiпg tиe coпditioпs of tиe щitиeгiпg дщдч of tиe stдte: tидt is tиe Mдгxist foгmцlд. Is it "coпtгдdictoгч"? Чes, it is "coпtгдdictoгч." Бцt tиis coпtгдdictioп is д liviпg tиiпg дпd щиollч гeflects tиe Mдгxist diдlectic.

• Welcome to PPCG and thanks for using the Sandbox! Unfortunately, this challenge is essentially the same as this question. Also, please don't write your specs in this "stylised" manner. It greatly hurts the searchability of your post. Aug 20, 2016 at 22:03
• Your code is also stylized. Does your code run properly? Aug 20, 2016 at 22:34
• @ColdGolf And do you think I'd stylize my post by hand? Aug 21, 2016 at 2:13
• @FryAmTheEggman OK, thank you. I now see my challenge was pointless and won't post it to the main. Aug 21, 2016 at 2:14
• Nothing is pointless: now you you know more and can come up with a better challenge! :) Aug 21, 2016 at 2:17
• @ColdGolf OK you were right, I messed up the stylization. {'b', 'и'} - here is a bug. Sorry. Aug 21, 2016 at 2:22
• @gaazkam Does your code, with the stylized цsiпg Sчstem;, run properly? Aug 21, 2016 at 2:39
• @ColdGolf I regard people of CodeGolf intelligent enough to find out they'd have to unstylize this code ^^ :) Aug 22, 2016 at 7:11
• @gaazkam I see. Aug 22, 2016 at 17:34

Alphabet ripple

You must print out this exact text:

abcdefghijklmnopqrstuvwxyzzyxwvutsrqponmlkjihgfedcba
abcdefghijklmnopqrstuvwxyyyyxwvutsrqponmlkjihgfedcba
abcdefghijklmnopqrstuvwxxxxxxwvutsrqponmlkjihgfedcba
abcdefghijklmnopqrstuvwwwwwwwwvutsrqponmlkjihgfedcba
abcdefghijklmnopqrstuvvvvvvvvvvutsrqponmlkjihgfedcba
abcdefghijklmnopqrstuuuuuuuuuuuutsrqponmlkjihgfedcba
abcdefghijklmnopqrsttttttttttttttsrqponmlkjihgfedcba
abcdefghijklmnopqrrrrrrrrrrrrrrrrrrqponmlkjihgfedcba
abcdefghijklmnopqqqqqqqqqqqqqqqqqqqqponmlkjihgfedcba
abcdefghijklmnopppppppppppppppppppppponmlkjihgfedcba
abcdefghijklmnoooooooooooooooooooooooonmlkjihgfedcba
abcdefghijklmnnnnnnnnnnnnnnnnnnnnnnnnnnmlkjihgfedcba
abcdefghijklmmmmmmmmmmmmmmmmmmmmmmmmmmmmlkjihgfedcba
abcdefghijkllllllllllllllllllllllllllllllkjihgfedcba
abcdefghijkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkkjihgfedcba
abcdefghijjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjihgfedcba
abcdefghiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiihgfedcba
abcdefghhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhgfedcba
abcdefggggggggggggggggggggggggggggggggggggggggfedcba
abcdeffffffffffffffffffffffffffffffffffffffffffedcba
abcdeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeedcba
abcddddddddddddddddddddddddddddddddddddddddddddddcba
abccccccccccccccccccccccccccccccccccccccccccccccccba
abbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbba
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa


Specs

• You may do it in all-uppercase instead of all-lowercase.
• A single leading and trailing newline are allowed
• You may not output an array of strings - the delimiter must be a newline

Scoring

This is . Program with lowest byte-count wins.

• Seriously, another alphabet challenge ._. Aug 21, 2016 at 14:23
• Duplicate, too lazy to find. Aug 21, 2016 at 14:27
• @LeakyNun you're too lazy to search through your own challenges...? Aug 21, 2016 at 20:49
• @trichoplax I don't feel like wasting my time to search for the duplicate. Aug 21, 2016 at 20:57
• @LeakyNun I knew what you meant - I was just making a poor joke that you would only need to search your own challenges since you wrote every alphabet challenge... Aug 21, 2016 at 21:15
• @LeakyNun, this Show tree rings age? Aug 23, 2016 at 10:50
• @LeakyNun what exactly is the duplicate? I'd like to know. Aug 27, 2016 at 16:39
• @ConorO'Brien this Aug 27, 2016 at 16:46

The Note-Takers Dream

Meta

This challenge requires more than most challenges. Is it to much?

The goal here is simple. Turn my notes into text. To this end, any tool or web service may be employed.

Specification

• Input
• An image of handwritten notes, stored an some data structure (this structure is flexible)
• This image will be a direct, over-head shot of a single page of graph paper
• Notes
• The notes are taken on graph paper with one character per box
• The characters will be printable ASCII
• An empty box should be considered as a single Space character
• There is an implicit New Line character between each row
• Output
• A string of the text represented in the image
• This image should be trimmed of leading white space
• Trailing white space is fine
• Score
• The score is the sum of the Levenshtein distances between required outputs and actual outputs
• Lowest score wins

Test Cases

Coming soon. . .

• Mathematica will win, and everyone else will weep Aug 30, 2016 at 22:42
• So basically codegolf.stackexchange.com/q/28207/194 with a larger character set and probably a smaller test set. It's effectively a dupe IMO. Aug 31, 2016 at 7:52
• Golfing in ABBYY FineReader Engine has never been so exciting. Aug 31, 2016 at 14:45

Print the name of the language

The goal of this challenge, as implied in the title, is to print the name of the language with a program in said language, in as few bytes as possible.

But that would be too easy, right ?

So to add a litle bit of challenge, you are not allowed to use any characters included in the language's name.

Rules

• Each submission must be a full program.

• The program must take no input, and print the name of the language to STDOUT plus an optional trailing newline, and nothing else.

• The program must not write anything to STDERR.

• Usual loophole rules apply

• Submissions are scored in bytes, in an appropriate encoding, usually (but not necessarily) UTF-8.

• This is , so the shortest program (in bytes) wins.

Sandbox

After checking, I don't think this question is a dupe.
Are there any grammatical mistakes ? (English isn't my first language)
Are there any rules that should be added (like banning languages created after the challenge ?) Should I add any further specification ?

• Do X without Y is discouraged. We're talking about your question in Code Golf Chat right now. (And now the conversation's moved on...) Sep 1, 2016 at 8:39
• @wizzwizz4 Would removing the "not use characters in the program name" rule make it better ? I didn't want the challenge to become "who has the shortest printf command" Sep 1, 2016 at 8:45
• At the moment it's "who has the shortest program name". Sep 1, 2016 at 8:48
• If the challenge is in danger of becoming "who has the shortest printf command" then rather than trying to fix it you should consider throwing it away and looking for an interesting challenge. Sep 1, 2016 at 11:42

Make a dummy C program

We all know the feeling. You have written a short, efficient and readable one-liner that's the perfect solution to the problem. Then your code-illiterate boss looks over your shoulder and is not very happy that you've spent an entire paid hour producing "nothing". You could politely explain the situation to your boss, complete with a demonstration that your code does what it should. Or, because talking to people is Hard Work™, you could fake it.

Your task is to write a program that takes a list of keywords as input, and outputs dummy C code that looks like it does something to do with those words. Sandbox note: not happy with the wording in final bit here.

For example, if the inputs were integral, formula, math, proof, fit and square, the output might be:

#include <math.h>
#include <setjmp.h>
double* squarefit(int integral, float* mathproof)
{
char **integralb={{0}};
double square[integral];
int i=0;

//integral math formula fit
for(integralb[0][0]=(char)erff(*mathproof);isnan((double)++integral);i++) {
return hypot(sqrt(square[integral]),integral)?square:square;
printf(*integralb,integral,*mathproof);
}
setjmp((struct __jmp_buf_tag*)mathproof+(int)(abs(--integral)-expm1l(integral)));
longjmp(0,0);
return square;
}


Although it doesn't have to do anything, or even run successfully properly, the source code produced by your program must compile in gcc (no additional options) without fatal errors. You do not need to provide a main function; if you don't, expect the line int main(void){} to be appended to the output file before it is compiled.

This is a , so the best-liked answer will win. However, voters should keep these questions in mind when assessing the submissions:

• Does the produced source code look like it does the expected task? Yes.
• Does the produced source code look like it has taken a long time to produce? Yes.
• Do different inputs result in the same program, just with different variable names? No.
• Does the produced source code look like the same code repeated over and over? No.
• Do your parents, grand-parents, co-workers or other "not computer people" think the produced source code was something to do with the input keywords (optional)? Yes.
• Would you think the produced source code was written by a person with knowledge of the C language, if you did not know that it was just dummy code (optional)? Yes.
• Does the code look readable (e.g. ungolfed)? Yes.

Not all of the standard loopholes apply for this challenge. For example, you mignt use external resources, such as library files or an indexable website. However, voters should use their discretion as to what is reasonable and what is not (such as expecting the "keywords" to be in a format that includes a high-quality, valid C program).

Sandbox note: how to finish challenge body?

• Is this a language-specific challenge?
– user56309
Sep 29, 2016 at 17:05
• @tuskiomi No, it's open to all languages. Sep 29, 2016 at 17:06
• Generally it's a good Idea to separate your challenge into five sections: the intro, summary, input, output, and examples. I'd recommend you do so here as well.
– user56309
Sep 29, 2016 at 17:07
• @tuskiomi Thanks, will do. Give me 6 to 8 weeks... Sep 29, 2016 at 17:11
• @tuskiomi I disagree. There are plenty of ways to organize a challenge effectively. However, this challenge looks like it might suffer a bit from the "art contest" issue, so be wary wizz. Sep 29, 2016 at 17:31
• @HelkaHomba I never said that it's the ONLY way to organize challenges to be effective, I said that generally it's a good idea to do that format.
– user56309
Sep 29, 2016 at 17:34
• @HelkaHomba That's the format I often use, and I plan to split it into headings. What do you mean by "art contest issue"? Sep 30, 2016 at 6:28
• I mean the judging is up to the whim of the voters own opinions and knowledge of how C code should look. We've had issues before with challenges like "draw the prettiest picture" which is plainly an art, not programming contest, and those kind of thing rarely go over well, often close voted as "primarily opinion based". This challenge (and all pop-cons really) suffer from similar issues. I'm not personally against this challenge or art contests, but it's just an issue you may need to face. Sep 30, 2016 at 6:35
• @HelkaHomba Do you have suggestions as to which questions to change / remove / reword to stop it being bad subjective? Sep 30, 2016 at 6:45
• I kind of like this, but I bet it would be closed as too broad. Anything from the program you provided to main(){integral+formula+square+proof+fit==math?return 0:return 1;} would be allowed. May 26, 2017 at 20:13
• @MDXF That wouldn't be valid if the inputs foo, bar, baz, fizz, buzz, fred would result in main(){foo+bar+baz+fizz+buzz==fred?return 0:return 1;}. Also, gcc gets very cross that none of those names are defined, so it won't compile. So actually that wouldn't be allowed. Also note that that is a boring submission to a popularity-contest. May 27, 2017 at 8:06

Urinal Discomfort!

This question springboards off of Positional Bathroom Etiquette, while adding an extra twist.

Background

I'm going to take @Nick Frev 's formulae for the total discomfort of a urinal spot

dist(x,y) = linear distance between person x and person y in Urinal Units
discomfort(x) = sum(1/(dist(x,y)*dist(x,y))) for all persons y excluding person x
total_Discomfort = sum(discomfort(x)) for all x
short_urinal_discomfort = discomfort_from_surroundings + 1/9 (inherent_discomfort)


Your task is to put a person into the spot with the least total discomfort. However, now you have big and small urinals. The small ones, obviously, cause a little inherent discomfort, so we prefer to not use those if we have a choice.

The Challenge

Input/Output

Your program will take in a string of 1,0,i,o to represent the row of urinals. 1 represents a person in a tall urinal, 0 is an empty tall urinal, i is a full short urinal, and o is an empty short urinal.

Using the above formulae, build a program that will replace an empty urinal with the correct placement of the next person(0->1 or o->i).

• The short urinals have an inherent discomfort of 1/9 which will be added onto the discomfort provided by the surroundings.
• The door is to the right of the row, so the urinals fill up right to left, because you have to pee really bad and can't walk further than you have to.

Input Output 000 001 101 111 1000001 1001001 101010101 101010111 000o 001o 100o 100i oo0oooo oo1oooo 11000ii 11010ii

Any tips would be super helpful

More test cases maybe? Or more clarification?

Stump the OEIS!

The OEIS is a wonderful database of integer sequences, but occasionally, there are code golf problems that generate integer sequences not found in the OEIS. Your challenge is to write some code that generates a sequence that meets all of the following criteria:

1. Sequence must not exist in the OEIS. Prove this by providing a link to the search for your sequence showing 0 results, such as this: 1,2,6,81,35246. In the spirit of good faith, please do not generate a sequence that is merely an existing sequence offset or multiplied by some constant.
2. The sequence must be non-repeating, non-oscillating, etc. Formally, there must not exist a subsequence S with finite length L, that begins at index I such that the subsequence from [I+kL] to [I+(k+1)L-1] for every k is identical to S. Such an invalid sequence would be 0, 1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3, ... because the subsequence 1, 2, 3 beginning at index 1 with length 3 also exists as the subsequence from 4 to 6, from 7 to 9, from 10 to 12, etc.
3. The sequence must contain a minimum of 3 distinct integers.
4. The sequence must be deterministic, e.g. there must not be any element of randomness in the generation of your sequence. Every time your program is run, it must provide the same exact sequence.

Please write code that provides as many integers in your sequence as feasible. At least 20 is recommended, though sequences that grow incredibly fast can provide fewer, provided you also give a proof that your code would produce that number if given enough time.

This will be a problem, so the entry with the fewest number of bytes wins.

A bonus of -20% can be applied to your score if, in addition to your sequence, you can also provide some mathematical justification for your sequence being included in the OEIS in the future.

Standard loopholes are disallowed, as well as sequences that are simply "this sequence is just the handful of numbers I came up with to fit this problem."

• You say "must contain an infinite number of entries not 0 or 1", then go on to talk about finite sequences, so I'm not sure what you're looking for here. Nov 17, 2016 at 17:44
• Changed it to "The sequence, if infinite, must contain" blah blah blah Nov 17, 2016 at 17:45
• This is definitely going to be closed as "Too broad" - if it isn't closed first as "Unclear what you're asking" because of the impossibility of testing whether "this sequence is just the handful of numbers I came up with to fit this problem." Nov 17, 2016 at 17:52
• @PeterTaylor If I removed the possibility of finite sequences, then IMO that second possibility goes away. As for being closed for too broad, there have been problems that don't have a single goal that have done well, such as Does this code terminate? that inspired a lot of very creative answers. Nov 17, 2016 at 17:59
• Its pretty easy to fill most of the requirements you've listed here: all you need to do is combine two different OEIS sequences (multiply or add). Restriction 3 should be changed to "Your sequence must contain at least 3 distinct terms". I'd also definitely recommend disallowing finite sequences, as well as the 20% bonus (which is very ambiguous) Nov 17, 2016 at 18:33
• @NathanMerrill That's a good idea for a change to #3, but as for being able to simply combine existing sequences, there's plenty of existing sequences like that are already in the OEIS even without necessarily being important. Nov 17, 2016 at 18:44
• @GabrielBenamy right, its not necessarily a bad thing, its just that most sequences generated aren't going to be that interesting. Also, what's to stop me from simply adding a random "9" number to the beginning of the sequence, or replacing the first term with "9"? Nov 17, 2016 at 18:45
• Consider the family of sequences parameterised by x where S(x, n) = n >= x ? n+1 : n. Only a finite number of those sequences are either in OEIS or a linear transform of a sequence in OEIS. Are they caught by "just the handful of numbers I came up with to fit this problem"? IMO it's ambiguous. Nov 17, 2016 at 19:22
• That's a good point. Is there any way to salvage this concept? Nov 17, 2016 at 19:24
• This is similar to the question "print something with no results on google". It got closed for being a question about Google's database, not about code-golf, so this one will probably be closed too. Nov 19, 2016 at 13:37

Golf + Polyglot + Circle = ?

In the original challenge, we asked you to do this:

Program | Language | Result
--------|----------|----------
A       | A        | Program B
B       | B        | Program A
A       | B        | Program C
B       | A        | Program C
C       | A        | "Wrong language!"
C       | B        | "Wrong language!"


Now we're asking you to do this*:

Program | Language | Result
--------|----------|----------
1       | 1        | Program 2
2       | 2        | Program 3
3       | 3        | Program 4
|    ...   |
X       | X        | Program 1
--------|----------|----------
1       | Any but 1| Any member of Set %
2       | Any but 2| Any member of Set %
|    ...   |
X       | Any but X| Any member of Set %
------------------------------
Set %   | Any lang | "Wrong language!"


(see original challenge for clarification)

Rules

• Do not grab source off of internet, or read own code from file
• Programs don't have to be distinct - you can make a polyglot quine
• Don't take input for any of the programs
• Different versions of the same language count do as different languages. (although this is discouraged because it leads to boring solutions)
• Standard loopholes apply

Scoring

Score is byte_count_of_program_one/2.75**languages_supported, the submission with the lowest score wins.

Template

Because of its length, the answer template is here.

*not that I'm expecting X to be so large

• +1 this comment if you think the title should be "Polyglot-Quine-Codegolf Returns!" Nov 23, 2016 at 23:38
• +1 this comment if you think the title should stay the same Nov 23, 2016 at 23:38
• Reply to this question if you have a better title Nov 23, 2016 at 23:38
• I personally think the title is way too descriptive, but "polyglot-quine-codegolf" isn't really descriptive enough. The problem is, I don't currently have a better idea... Nov 24, 2016 at 0:12

Signs in Permutations

Introduction

Let's take the permutations of 123.

123
132
213
231
312
321


We can insert signs in between the numbers and count how many > signs there are:

1 < 2 < 3 # 0
1 < 3 > 2 # 1
2 > 1 < 3 # 1
2 < 3 > 1 # 1
3 > 1 < 2 # 1
3 > 2 > 1 # 2


We can arrange this in a table with n corresponding to the number (in this case 3) and k corresponding to the number of > signs, you get this:

┌───┬───┬────┬─────┬─────┬────┬───┐
│n\k│ 0 │  1 │  2  │  3  │  4 │ 5 │
├───┼───┼────┼─────┼─────┼────┼───┤
│ 1 │ 1 │    │     │     │    │   │
│ 2 │ 1 │  1 │     │     │    │   │
│ 3 │ 1 │  4 │   1 │     │    │   │
│ 4 │ 1 │ 11 │  11 │   1 │    │   │
│ 5 | 1 │ 26 │  66 │  26 │  1 │   │
│ 6 │ 1 │ 57 │ 302 │ 302 │ 57 │ 1 │
└───┴───┴────┴─────┴─────┴────┴───┘


Given an n and k, print the number in the table corresponding to that n and k.

Remember, this is , so the code with the fewest bytes wins.

Related OEIS sequence

• Dupe Dec 1, 2016 at 22:07

I want to post the question here to make sure it is suitable.

Question: Word Equations

Given a word equation, the solution must output the answer.

My definition of a 'word equation' is an equation where the operators are words.

The operators will be spelt as

add minus times divide

The solution must take one input

The solution must give one output

Examples:

Input: 7 add 8 Output: 15

Input: 9 times -2 Output: -18

Input: 24 divide 2 Output: 12

Input: 4 minus 5 Ouput: -1

You are not required to deal with divide by zero errors.

Fewest characters will win

Feedback is welcomed

• What is the winning criterion? Dec 2, 2016 at 22:14
• @daHugLenny fewest characters, should have known to include that Dec 2, 2016 at 22:59
• Be aware that you will receive many answers in the form: substitute words with corresponding char (+-*/), then evaluate the string you got. Non necessarily a bad thing, just pointing this out in case you expect people to build a calculator from scratch.
– Leo
Dec 3, 2016 at 18:41
• @Leo the way I expected to solve it was by char substituting. However building a calculator from scratch only using + and - could be an interesting challenge Dec 3, 2016 at 18:55

GoL flooding

Considering a 1000x1000 grid (no wrapping, borders dead), your task is to grow the maximum "stable" population from the fewer individuals.

For the purpose of this challenge, the definition of stable is a configuration who repeat with a period of less than hundred(100) generations.

Scoring

Your score is lowest number of live cells in your stable population divided by the number of initialy live cells, highest score win

meta post about on topicness

• How many generations does the simulation run before the score is tabulated? Dec 8, 2016 at 13:48
• @TimmyD I would say 10.000 but feel free to suggest a better number if you think it could improve
– Sefa
Dec 8, 2016 at 14:07

Convenient Palindromic quine golf, Cops cops-and-robbers

This is the cops thread, the robber's thread is here.

Cop's Challenge

A program is conveniently palindromic if

it is equal to the string derived when its reverse has all its parentheses (()), brackets ([]), and braces ({}) flipped. No other characters are special and require flipping. (<> are sometimes paired but often not so they are left out.)

copied from this challenge.

Write a conveniently palindromic program that prints its own source. This is the robber's goal:

• Remove byte(s) from the cop's program so that the resulting program:
• prints the original source, or
• prints the new modified source
• Resulting program need not be a convenient palindrome

A counterexample

JavaScript

(function $(){console.log('('+$+'())')}())//((){('(()'+$+')')gol.elosnoc}()$ niotcnuf)


is easily cracked because the robber can remove all the characters past the comment and it will still print its own source.

Rules

• Program must be longer than one character
• No reading from a file or grabbing from an external resource
• Submissions that aren't cracked for 7 days are marked as "safe", and cannot be cracked anymore
• Cop's submissions after XX/XX/XX are non-competing (can be pushed back depending on popularity), so there are still robbers around to crack it
• The shortest safe solution in bytes wins.
• Robbers won't have a chosen winner

• This is basically just a "comment-free palindromic quine" challenge, right? When those challenges have been run elsewhere, the comment-freedom has been verified via brute forcing rather than via a robber, and I suspect that the robbers might not have much to do here. (That said, some languages are slow enough that brute-forcing their correctness would be difficult.) In other news, you should probably require proper quine rules, even if we can't quite define them; under your current rules, 1 is a valid palindromic quine in PHP.
– user62131
Dec 9, 2016 at 22:41
• I would possibly change the palindrome restriction to convenient palindromes, as these are way easier to implement in most common languages such as JS and Python. Dec 9, 2016 at 23:01
• @ais523 1. Yas. That was my aim! 2. It's difficult to implement a brute-force solution for a longer submission, how would that work? 3. Program must be longer than one character 4. Thanks. Dec 10, 2016 at 14:27
• 11 then :-P. Also, in a way I think this might be more interesting with true palindromes, as it forces you to hide the backwards string somehow, but I agree that it would disqualify a lot of languages.
– user62131
Dec 10, 2016 at 14:40
• @ais523 I'll do a true palindrome one then a convenient palindrome one later, perhaps? (also 11 then means ?) Dec 10, 2016 at 14:44
• @ais523 When those challenges have been run elsewhere, they have? Dec 10, 2016 at 14:51
• Neither this challenge nor this challenge has the same task as yours, but they both disallowed comments in much the same way as this one (i.e. by ensuring that deleting from the program breaks it).
– user62131
Dec 10, 2016 at 15:27

Prelude:

Joke languages are allowed.
Submissions' scores will vary depending on whether they'll be made in a joke language, golfing language or a Turing complete language, don't worry if your score is high just because you chose a TC language.
That being said, let's get right into the challenge...

Challenge:

Make a program as close as possible to the language name and document what it does in the description.

Scoring/rules:

(will assume a simple language I made up, called Printr that has only a print() command that can take a argument to print but doesn't have to)

• Submissions that contain more than a 1/2 of whole language name in a string (ex. print("Printr")) are banned.
• Submissions must not throw any errors/exceptions/warnings (writing to an error stream is okay though).
• +1 for every char away from language's name (ex. print("r") is 4 chars away, (""), +4 points)
• Submissions need to contain (at least once) the language name "in a row" excluding nonalphanumeric characters and ignoring case (ex. print(" *@)!R") is okay, print("lolz R") is not okay)
• Duplicates of the name will be counted as other characters (ex. print("r") print("r") is still 4+1 [space]+10=15).

By looking as close as the language I mean having the least score (since scoring is based on other characters than the language name itself.

Example:

Printr, score 4:

print("r")

This program prints "r" then quits.

• is it allowed to throw an error? Dec 18, 2016 at 14:00
• @Flp.Tkc, good question, errors shouldn't be allowed (syntax error be like). Dec 18, 2016 at 14:07
• What about a warning to STDERR? Stray error output is allowed by default on meta... Dec 18, 2016 at 14:19
• @Flp.Tkc, should be okay. Dec 18, 2016 at 14:24
• ><>, in ><>, score 0, infinite loops. Dec 18, 2016 at 15:56
• or actually if we're excluding non-alphanumeric characters, this could also be golfed down to > or empty depending on if outputting "something smells fishy..." is a valid program. Dec 18, 2016 at 16:00
• in brainfuck you can just write brainfuck and it won't do anything... Dec 19, 2016 at 17:31

Print number of possible values of X if:

• Code 1: X is dividable by 3, X contains the number 3 and input() < X < 10000
• Code 2: X is dividable by 7, X contains the number 2, X doesn't contain the number 3 and input() < X < 5000

Sub-Challenge:

Do the same but instead of printing the number, print the values

Disclaimer: This is my first code golf challenge, and it's very simple, but could bring up some really short answers and cool languages

• First thing: Sub-challenges are not a good idea. People will write the shortest code they can and just disregard the sub-challenge. Jan 16, 2017 at 19:49
• Should you output the sum of the numbers from both two bullet points, in one? I don't think it benefits the challenge to have two different upper limits. I can see why you want it there, but I personally don't think it's a good thing. This needs some good test cases. Jan 16, 2017 at 19:52
• Those were actually different puzzles, sorry! Jan 17, 2017 at 12:10
• Two different independent puzzles in one challenge is not a very good idea either I'm afraid. I think it would be better to use the same upper limit and require the numbers from both 1 and 2 together, I.e. the union of the two sets. Jan 17, 2017 at 12:23

[please suggest a name]

Mark got an idea of making a path finding algorithm for auto driving vehicles.

Unfortunately, Mark doesn't yet know about programming, so he decided to get help from the code golfers.

How should it work?

First, we input how many 'nodes' there are. we call it 'N', and its an integer up to 16 bit values.

Second, we input what nodes are connected to each nodes, and the length of the connection. for example, if the diagram is

(1)-5-(2)-2-(3)

the input should be

2 5  //node 1 is connected to node 2, and the length is 5
1 5 3 2 //node 2 is connected to node 1 and the length is 5. and its also connected to node 3, and its length is 2.
2 2  //node 3 is connected to node 2, and the length is 2.


then, finally, the starting node, and the final node. they are inputted as node numbers.

Examples

Input:

3
2 5
1 5 3 2
2 2
1 3


Output:

1->2->3

Explanation:

(1)-5-(2)-2-(3) starts from 1, and ends in 3. there is only one path, and it is the answer.

Specs

Standard rules apply.

• Possible duplicate. And another related question. Suggested tags for this challenge: graph-theory and path-finding Jan 17, 2017 at 9:35
• Not a duplicate. Though related, clearly not a duplicate. Jan 17, 2017 at 10:32
• By the standards of this site, it is a duplicate. Jan 18, 2017 at 11:48
• Proof of duplicate? Jan 18, 2017 at 11:50
• Currently the only differences are that not all nodes are necessarily connected and the specified input format. However both input formats are tight and string based, so I'd like to see this challenge with a loosened input format, e.g. allow all reasonable input formats for a weighted graph. Jan 18, 2017 at 11:53
• Okay, thanks for the suggestion. @Laikoni Jan 18, 2017 at 11:55
• The way we identify duplicates on this site is to ask "Can answers from one question be copied over to the other with little or no modification and still be competitive?" Jan 19, 2017 at 7:09
• @trich Seems legit, but those two question have quite of a difference, and second, I have came up to this idea all by myself, and being tagged as dupe, seems a tad unfair. Jan 19, 2017 at 12:12
• Being marked as duplicate doesn't mean "This is a bad challenge", it just means "This challenge has already been posted". This is a good challenge idea, but we only host each challenge once, so that all the answers are in one place. Jan 19, 2017 at 13:42

Generate "N" random numbers which their sum is exactly "N"

Your goal is to generate N pseudo-random numbers R, then sum or subtract all the R togheter and obtain as result N.

Rules:

• You get N from standard input as integer number, such as N <= 1000.
• You can't perform operations like sum 100 times 1, 50 times 2, or similar...
• R shall be generated in any reasonable non-deterministic way
• R shall be integer such as 0 <= R <= N.
• R can't have a constant value each time you generate it. For example you can't generate R with methods like R = rand(1,2) with the result that 1 <= R < 2 (R is constantly always =1), and then sum R 100 times.
• You can perform only sums or subtractions of the generated R's.
• You have to sum or subtract the newly generated R to the total of R's.
• Standard loopholes are forbidden.
• This is so the shortest code wins.

Example 1:

1. Get N=100 from standard input.
2. Generate 100 pseudo-random integer numbers R such as 0 <= R <= 100.
3. Sum or subtract all the R and obtain 100(N) as result.

Example 2:

1. Get N=20 from standard input.
2. Generate 20 pseudo-random integer numbers R such as 0 <= R <= 20.
3. Sum or subtract all the R and obtain 20(N) as result.

Not-so-smart-but-working example in C#:

using System;
public class Program {
public static void Main() {
int S = 0, N, R = 1, X;
int INPUT = Int32.Parse(Console.ReadLine());
Random rnd = new Random();
for (int I = 1; I < (INPUT+1); I++) {
X = (INPUT+1) - I;
if (I == INPUT && S == INPUT) {
R = 0;
}
N = rnd.Next(R, X);
if (S <= INPUT) {
S = S + N;
} else {
S = S - N;
}
Console.WriteLine("I = {0}      N = {1}     S = {2}", I, N, S);
}
}
}


Test online

• I don't understand what the goal is. If my program accepts the number 20, I have to generate 20 random numbers that sum to 20? So I generate random real numbers? Integers? Positive integers? Positive-or-zero integers? Jan 19, 2017 at 15:27
• "You get N from standard input as integer" and "N shall be generated in any reasonable non-deterministic way" seem incompatible. If these are referring to two different things, then it would be clearer to not call them both N. Jan 19, 2017 at 15:42
• It's not clear to me what your working definition of "random number" is, especially given that the system to be implemented has fewer degrees of freedom than "random" numbers. For a question about random numbers to be well specified it should state the distributions to be followed (modulo limitations of PRNGs). Jan 19, 2017 at 21:17
• @GabrielBenamy Yes you understood correctly the challenge. I changed it adding more specs and more details. If you have further doubts please let me know. Jan 20, 2017 at 8:03
• @trichoplax Thanks for your comment. I edited the question to make it more clear with more details and specifications. Please let me know if I can improve it in a better way. Jan 20, 2017 at 8:04
• @PeterTaylor I am not sure I get what you mean, probably they are too advanced concepts for me :) Anyway I largely edited the question to make as more clear as possible. If you think it needs to be improved please give me your suggestions on how to make it a more clear and better challenge. Jan 20, 2017 at 8:07
• What about cases where it is impossible to sum/subtract to R? For example: N=5, R=[0,1,1,1,1]. Jan 20, 2017 at 9:46
• @Emigna if you try my C# example it works for N=5. Jan 20, 2017 at 11:22
• If random distributions are too advanced a concept for you then I think you should abandon the idea of trying to post a question about sums of random variables. Jan 20, 2017 at 11:23
• The explanation is still unclear, and needs work in itself. Separately from that, I recommend example inputs and outputs (literal output rather than explanation). The specification should be unambiguous before seeing the examples, and then the examples should come afterwards to confirm correct understanding of the spec. At present I believe the intention is to output an expression containing N integers, each added or subtracted, each in the range [0, N], evaluating to N, and for the integers to be randomly distributed amongst those that meet these criteria. Jan 20, 2017 at 11:55
• @trichoplax thanks for your comments and explanations, although the challenge seems clear to me it's obvious that I am missing something that goes beyond my knowledges. I think I will delete the post maybe reviewing it. Jan 20, 2017 at 12:24
• @PeterTaylor I got an idea and I posted it here to have feedbacks about it and maybe help or suggestions for improvement, but as I said obviously I am missing something that I haven't studied. I'll delete the challenge. Jan 20, 2017 at 12:28
• A post always seems clear to the person who wrote it, because they already knew what they meant. That's why the sandbox is so useful - I can't tell if my challenge is really clear until I show it to other people. Being unclear doesn't make it a bad challenge. It just means it needs rewording before it will be ready. Here in the sandbox you don't need to delete. You can simply keep making adjustments and getting feedback until it's ready. Jan 20, 2017 at 13:17

Make the Shape

This is a wider version of this question, so it may not get posted.

Given a single character e.g. H or ! and a sequence of letters e.g. abcdefghijklmnopqrstuvwxyz you must output the character drawn using the letters in the sequence. If you need more letters, just loop through the sequence again.

Input

A single character, c. You can assume that it will always be one character.

A sequence of charaters s. All characters must be printable ASCII letters.

Output

c made up of the letters in s

Examples

Let's say c = "H" and s = "abcdefghijklmnopqrstuvwxyz". The correct output would be

ab   cd
ef   gh
ij   kl
mnopqrs
tuvwxyz
ab   cd
ef   gh
ij   kl


c = "!" and s = "hello, world" outputs

he
ll
o,
w
or

ld


Rules

• Shortest code (in bytes) wins
• Any correct output may be outputted i.e. either one of the example
• c must be one character
• Leading/trailing newline is acceptable
• Standard golfing loopholes apply
• Lines must be 2 characters thick
• You must use every letter in s at least once to make c
• Either a full program or a function, NO snippets
• You need definitive rules about the shape and size of each letter or else this will probably be closed as unclear. Jan 22, 2017 at 17:35
• This is similar to another question, that I can't find at the moment. It's about making words from other words, nested n times. Jan 22, 2017 at 18:42
• "Both inputs must be surrounded by "" - um, why? This isn't a parsing challenge. Input should be allowed to be taken in any reasonable format, as is the code-golf standard. You should only break the IO defaults if it is of paramount importance to your challenge, whereas it just looks like a trivial pointless rule here. Jan 22, 2017 at 18:49
• It was to clarify for languages that need " at input. I'll change it.
– user63571
Jan 22, 2017 at 19:06
• Also whoever downvoted can you tell me why? I might be able to improve the question
– user63571
Jan 22, 2017 at 23:26
• If you want to limit it to alphabetical characters, you may use my list of ASCII art: codegolf.stackexchange.com/questions/99913/5-favorite-letters Jan 23, 2017 at 19:36
• Also, Jack, they're probably downvoting because of how open-ended it is. You haven't defined the layout of any of the characters beyond H!. Jan 23, 2017 at 19:52
• Thanks for the help
– user63571
Jan 23, 2017 at 20:24
• If you want to reply to someone, tag them - @JackBates Jan 23, 2017 at 22:49

Why is it buff...........ering?

As the Internet isn't perfect, occasionally the videos we watch start buffering. When this happens, I get very annoyed. As the wait gets longer, I get even more annoyed.

Your task is to write a function or program that waits a random amount of time and then outputs an angry message with the level of anger increasing the longer it waits

None

Output

An angry message and the length of the wait

Examples

Time waited: 5 seconds

Angry message: Never mind!

Time waited: 30 seconds

Message: I hate YouTube!

Time waited: 1 minute

Message: Die computer, die!!!

This code is an example in Python, obviously ungolfed.

import time
import random
messages = ["Never mind!","Getting annoyed","I hate YouTube!","Die computer, die!"]
slept = random.randint(5,60)
msg_num = slept//len(messages)
time.sleep(slept)
print("Time waited:",slept)
print(messages[msg_num])


Rules

• Messages are up to you
• The time to wait ranges from 5 seconds to 1 minute
• Standard code-golf rules apply
• Standard code-golf loopholes are disallowed
• This won't work as code-golf because it'd mostly be about golfing the angry messages in question, and golfing English is always highly subjective; how angry does the message have to be before it qualifies as "angry"?. I don't really see it working with another victory condition, either.
– user62131
Jan 25, 2017 at 19:14

Don't know what to call this

Some people here may be familiar with Euler's identity. If not click the link

Now you know what the equation is, what if we change it slightly? No-one like to imagine numbers so instead we're going to use an unknown number x.

So first we get rid of i and replace it with x. Now we all know that i*i is -1. But with i gone, so must -1. Let's change it to x^2 instead. However this means there is only one solution. So instead let's make it x^random_integer(0,x) to spice it up

If we change the equation from e^(i*π) - 1 = 0 to e^π / (x^random_integer(0,x)) = 0 we now have something we can work with.

Given an integer or float as input, x, calculate if it satisfies the above equation. Your code should result in True or False or the closest equivalent.

Input

A single number between -(2^32-1) or what ever your language can handle and 2^32-1 or whatever it can handle called x

Output

A Boolean that says whether the number satisfies the above equation and the random number that is picked

Rules

• The code must calculate if x fits this equation rather than take it from an outside source

• Results in True if within -0.1 and 0.1

• This is code-golf so shortest code (bytes) wins

• Builtins that postdate this challenge are allowed unless they are specifically designed for the sole purpose of winning this challenge

• Standard code-golf loopholes apply

Examples

x = 5
e^π / 5 ^ rand(0,5) = 0
rand(0,5) = 2
results False (0.92)

x = 6
e^π / 6 ^ rand(0,6) = 0
rand(0,6) = 4
results True (0.01)

• Most languages don't have accurate enough floats to be able to compare the two sides as equal. As such, they could just arbitrarily return false. You might want to add a precision level. (Also, I assume there are only finitely many solutions anyway…)
– user62131
Jan 25, 2017 at 20:19
• Sorry I'm a bit all over the place. I'm not perfect with the maths and keep changing it so it might work :/
– user63571
Jan 25, 2017 at 20:30
• I found something that works! :)
– user63571
Jan 25, 2017 at 20:44
• Check rules number 2 and the examples
– user63571
Jan 25, 2017 at 20:55
• According to your equation the rule number two has both of those as false, 0.92 and 0.64 are not 0.1 away from 0. Random numbers are also usually considered a bad thing to be using in the challenges. Jan 25, 2017 at 20:56
• Sorry got the example wrong, fixing now. I thought it was to 1 while I did the first one :/
– user63571
Jan 25, 2017 at 20:57
• e^π / (x^random_integer(0,x)) = 0 requires e^π = 0 (false) or x^random_integer(0,x) to be infinite (in which case it's not strictly true, but it is in the limit). The only way it's going to be infinite with real x and non-negative random_integer(0, x) is if x is infinite. Therefore the explanation of the task effectively states that the task is to return False. It's very confusing that the rules then contradict this. Jan 25, 2017 at 23:06
• @PeterTaylor If you look at rule 2, it explains how to beat this. Also check the example true one
– user63571
Jan 25, 2017 at 23:09
• My point is precisely that rule 2 and the second example contradict the problem statement, which therefore needs fixing. Jan 25, 2017 at 23:26
• I'm not sure if I understand you correctly. The problem is to find if x satisfies the equation e^pi / x^rand(0,x) = 0 plus-minus 0.1. Rule 2 and the examples both follow this problem and output the correct result.
– user63571
Jan 25, 2017 at 23:32
• The problem statement clearly says "Given an integer or float as input, x, calculate if it satisfies the above equation" where the above equation is e^π / (x^random_integer(0,x)) = 0. Then half a screen later the rules say, in effect, "Actually, what I said earlier was a lie." That's not the way to write a clear specification. One way to fix it would be to change the problem statement to say "If we change the equation from e^(i\*π) - 1 = 0 to e^π / (x^random_integer(0,x)) = 0 we now have no solutions, so let's make it an inequality: abs(e^π / (x^random_integer(0,x))) <= 0.1". Jan 26, 2017 at 8:34
• What rules make it say "What I said earlier was a lie"?
– user63571
Jan 26, 2017 at 15:34
• Loophole found: Consider a/(x^b): For a non-zero a, this fraction gets closer to 0 as x^b gets closer to infinity, where higher values for b result in outcomes closer to 0. As such, if you want to check if the fraction is smaller than some other value c if b goes from 0 to x, you only have to check if a/(x^x) < c, because if that's false, there will be no value for b smaller than x for which it is true.
– Luke
Jan 26, 2017 at 19:03
• What's your point? Are you suggesting I change it in some way?
– user63571
Jan 26, 2017 at 19:28
• You should at least remove the word "random" from the question, since this has nothing to do with randomness. The question is stated a lot more complicated than it actually is.
– Luke
Jan 26, 2017 at 20:07

Count My Change

Your task is to sort an array containing the strings "quarter", "dime", "nickel", and "penny" any number of times in no specific order and sort them so that they are in this order: quarter dime nickel penny (in other words, greatest to least monetary value).

Rules

1. Your program must take an array as input containing the names of U.S coins and sort them from greatest to least by monetary value.
• For those who are not from the U.S or don't use change, the values of U.S coins, from greatest to least, are:
• Quarter: 25 cents
• Dime: 10 cents
• Nickel: 5 cents
• Penny: 1 cent
2. You may sort this array in any way you wish, as long as the output is ordered by the monetary values shown above.
3. Input can be taken in any way, be it command-line arguments or STDIN.
4. An input array would be all lowercase strings, something like this:
• quarter dime nickel nickel quarter dime penny penny
5. If there is a value in input that is not a quarter, dime, nickel, or penny, your program should output 0 .

Test Cases

• penny nickel dime quarter should become: quarter dime nickel penny
• nickel penny penny quarter quarter quarter dime dime dime dime
• quarter dime nickel nickel quarter dime penny penny
• euro quarter nickel dime would output 0 because a euro is not U.S currency.
• esac (not a test case, I just like bash a lot)

This is , so standard rules & loopholes apply.

• Test cases please? Feb 3, 2017 at 16:01
• @MistahFiggins On it Feb 3, 2017 at 16:26

A simple challenge: Shortest program that takes the longest to compile.

• What's the scoring requirement (i.e. how will programs be scored)? Who's machine will this be run on? Feb 11, 2017 at 1:43
• It's too broad of a challenge; are infinite loops allowed? To reiterate what Qwerp-Derp said, how will it be scored? Longest to compile -- what if it's an interpreted language?
– user42649
Feb 11, 2017 at 1:47
• @AlexL.: languages without a compiler would be excluded. Feb 11, 2017 at 1:57
• I still believe this is not a good challenge because it is unclear what you are asking and it is too broad.
– user42649
Feb 11, 2017 at 2:01

Introduction

What we have feared for so long has finally happened, the robots have gained counsciousness and have risen. There has been a war, a global and violent one, and humans have been defeated.

Calcubot, the fearless and tyrannic robot leader, has established a new world order, and its first decree as Supreme World Leader has been to forbid all non-AI entities from using numbers.

But, as it's always been the case in oppressive regimes, the Resistance has begun to form. Their first act of rebellion is to print leaflets with numbers on them. However, as the secret robot police is everywhere and can see everything, especially computer programs, these leaflets have to be inconspicuous and must not use numbers within their construction.

Challenge

The goal of the challenge is to print all digits from 0 to 9 without using them in the source code.

Example Input and Output

Input:

There is no input required

Output:

0123456789

Restrictions

The source code must not use one of the following characters : 0123456789.

Also, as this is a challenge, your code must be inventive, i.e. please refrain from using prebuilt classes with all the digits or other standard loopholes. You might still try to make your source code the shortest possible, but not at the expense of inventivity.

The answer with the most upvotes after 7 days will be declared the winner, the time of submission will be used as a tie-breaker.

For example, this is what I had in mind for a PHP solution :

$i = (int)false; foreach(str_split('abcdefghij') as$k) {

Google search result short summary

Intro

When you search in google, it always shows you a result with a sample text from the found webpage.

For example if you search for "Madonna greatest vinyl", google will show you one line link, and below a short excerpt from that found webpage:

Madonna Greatest Hits Records, LPs, Vinyl and CDs
Madonna - Greatest Hits Volume 2, Madonna, Greatest Hits ... vinyl Is Fully Restored To As Near New Condition As Possible. Shipping & Multiple Order D..

Imagine yourself you work for google and you have to write a program/function which takes in:

• a string containing many words (the webpage content)
• list of searched words (at least 3)

and returns the shortest excerpt of given string (webpage) containing all searched words.

Example

Given this webpage content:

This document describes Session Initiation Protocol (SIP), an application-layer
control (signaling) protocol for creating, modifying, and terminating
sessions with one or more participants. These sessions include
Internet telephone calls, multimedia distribution, and multimedia conferences.


and these searched words:

calls, sessions, internet

the program should return:

sessions include Internet telephone calls
, as this is the shortest substring containing all 3 searched words. Note that one more substring contains these 3 words, it is "sessions with one or more participants. These sessions include Internet telephone calls", but it is longer, so it was discarded.

Rules

• If the string is empty, return empty string
• If all searched words are not found in given string, return empty string
• Search is ignoring letters case
• At least 3 words need to be specified for searching
• The returned string may contain the searched words in different order than specified

Challenge

Write the fastest code. It's for google, right? Remember that repeatable strings comparison is very expensive.

• There is not always a short summary. Mar 10, 2017 at 18:19
• Fastest code is going to be tough to measure on this, as even pretty large chunks of text will still result in very small amounts of time. Mar 10, 2017 at 18:50
• You should include more test cases, especially large ones if you want to score by fastest code. Mar 12, 2017 at 19:04
• @fəˈnɛtɪk There is, if all searched words are found in the given string. (For some definitions of short...) Oct 7, 2017 at 11:22

It's 42!

This challenge is to code golf a program that proves that the next number in a pattern is 42 based on the website Actually it's 42.

In your program, the user inputs a pattern of numbers and it has to output the equation that proves that the next number is 42.

For example, the user inputs the pattern 1, 2, 3, 4, 5 the output is something like:

f(n)=9/2(n^2)−17(n)+29/2

Because f(6) = 42

Your program can output any form of an equation that makes the next value in the equation 42.

Your outputted equation must be able to also output the numbers in the original input also in the form of a variable. For example, in this equation, if you put 1 as the number input you get the number 1.

Your program cannot make any HTTP requests to APIs, in other words, all the calculations must be done in the program.

Good Luck!

• You might want to make your question a bit clearer. Explain input format is first n terms of a sequence. Seems like an interesting idea though Mar 13, 2017 at 1:38
• It seems to me like this challenge is two disjointed parts. 1) is recognizing the pattern of numbers and determining the next, and 2) is turning an arbitrary n into 42. For 1, you should be clearer about which patterns must be recognized (arithmetic sequences? Geometric sequences? More?), and for 2 you probably need more restriction. For example, what's stopping me from outputting n - n + 42 regardless of input? Mar 13, 2017 at 1:59
• @DJMcMayhem Good point that I have not thought about. Mar 13, 2017 at 10:33
• Making edits to it Mar 13, 2017 at 10:34
• @DJMcMayhem You can't always output n - n + 42 because it won't fit the previous numbers in the sequence. That is if OP wants the challenge to be to implement the functionality of the linked site. Mar 13, 2017 at 13:07
• However the algorithm used by the site is (according to the why page) is to solve a system of linear equations, and this has been done before: codegolf.stackexchange.com/questions/22573/… Mar 13, 2017 at 13:10
• @laikoni Oh, I thought the sequence was the list of inputs, not the list of outputs. I completely misunderstood the challenge. Mar 13, 2017 at 13:17
• Looking at the sole example in the question, the challenge seems to be to output a random function independently of the input. Is this correct? If so, ditch the input. If not, it's a dupe Mar 13, 2017 at 13:50
• @PeterTaylor the input is required to be taken part in the equation. Hense the rule. You have to output the equation DJMcMayhem Mar 13, 2017 at 14:09
• @Laikoni Well this makes an equation so it does not have to do with that. Mar 13, 2017 at 14:10

The Mnemonic Major System

People frequently need to memorize long strings of digits, such as telephone numbers. Fortunately, the mnemonic major system, which uses sounds to represent digits, and words to represent strings of digits, can help.

• /s/ and /z/ represent the digit 0
• /t/, /d/, /θ/ and /ð/ all represent 1
• /n/ represents 2
• /m/ represents 3
• /r/ represents 4
• /l/ represents 5
• /tʃ/, /dʒ/, /ʃ/ and /ʒ/ all represent 6
• /k/ and /ɡ/ represent 7
• /f/ and /v/ represent 8
• and /p/ and /b/ represent the digit 9
• For the purpose of this challenge, the sound /ŋ/, generally written as ng, counts as 27.

All other sounds can be used to create words, but do not represent any digits. Thus, the words Code Golf represent the digits 71 758. Since the mnemonic major system is a phonetic system, silent letters do not represent any digits. Thus, the word knight represents the number 21, not 7271. The letter x is pronounced /ks/, and thus represents the digits 70. On the other hand, most double consonants are not actually pronounced separately (e.g. mummy, chicken), and represent only one digit.

Challenge

Your task is to write a program or function that takes a string of digits in any convenient format as input and returns a mnemonic representation of those digits as output. The following rules must be observed:

1. You must use real English words. Acronyms and abbreviations are not allowed. If in doubt, refer to an authoritative dictionary.

2. Whenever possible, two or more digits must be represented by a single word. If the number of digits is odd, you may choose which digit, if any, stands alone (see examples). All two-digit numbers can be represented by English words.

You may use a built-in or external dictionary to search for suitable words.

This is code golf, so the shortest solution wins.

Example Input and Output

758
golf, kale fee, key leaf

0142710
strengths, suitor nugget saw, seat run key tease

2362185
unimaginatively, gnome gin devil, enmesh native lie

• Getting the sounds from a word is not a task that computers can do properly due to the English language not actually following the rules it supposedly has. Mar 13, 2017 at 16:51
• The supplied link to M-W.com is pretty useless. To make a reasonable question you should provide a link to a single file which includes a word list with phonetic representation in easily parseable form. That would also allow verification that the requested task is possible, which at present I doubt: are all 1000 possible three-digit groups really representable? E.g. 333 seems like a tough one to represent. Mar 13, 2017 at 16:58
• On a separate issue, the calculation of pi has been done to death, so the interesting part of the question is the mapping from a sequence of digits to a sequence of words. On that basis I would recommend removing pi from the question and instead taking a sequence of digits as input, putting the focus squarely on the interesting part. Mar 13, 2017 at 16:59
• On the dictionary issue, just make the program take the dictionary as an input (and let people use whatever dictionaries they want to test their program, given that you could get the answer you want by substituting your own). It's not like hardcoding the dictionary is possibly going to save bytes here, given that even languages with dictionaries built in would have a different dictionary to the one you wanted.
– user62131
Mar 14, 2017 at 4:44
• @PeterTaylor Thanks for your input. Whether all three-digit groups are representable is irrelevant for the question as is, since only three three-digit groups need to be represented. However, I think your proposed changes would improve the question. I will do some research on the problem of representing arbitrary three-digit numbers. Mar 14, 2017 at 6:19
• @fəˈnɛtɪk Well, English spelling was pretty consistent when it was introduced around 1400. However, written language is generally more conservative than spoken language. While it is difficult to determine how a given word is pronounced, it is not so difficult to construct a word to match a given pronunciation. Mar 14, 2017 at 6:22

Print the Previous Program

Specifications:

You must print the exact text of the previous answer without ever having a sequence of more than 5 letters in a row in your program that also show up in the previous answer (prevents hardcoding). Your program must only use UTF-8 characters.

You may repeat a language; however, you may not post twice in a row and no two of your consecutive answers may be from the same language class (different versions are treated as the same language).

The first language is to print the exact text "Hello, World!"

0-byte submissions are not allowed.

By the way, this is just a draft, it might be a dupe or really closely related, and probably has more holes in it than Swiss cheese so please give me any suggestions you have. Thanks.

Also, my drafted scoring system is something like bytes / answer_num where answer_num is which answer yours is (on a time scale).

• "letters" isn't clear, because there are a bunch of Unicode characters that aren't letters. Requiring that no sequence of 5 Unicode characters can be repeated would be better. Additionally, it's traditional in answer chaining challenges for the first program to be provided in the challenge.
– user45941
Mar 19, 2017 at 4:44
• I don't like the 5 letters in a row thing, I think there should be more finegrained restrictions on hardcoding. Additionaly, someone could just do a couple of transformations on program text. Mar 19, 2017 at 4:47
• I'm confused by this "prevents hardcoding" as hard-coding a string is exactly the problem statement. Mar 19, 2017 at 5:13
• @Mego Right, I meant characters. And also, if that's the case, I'll make a program to start off with then. Thanks!
– user42649
Mar 19, 2017 at 16:47
• @Mendeleev That is true. Do you have any suggestions? I'll keep thinking of better ways to restrict that.
– user42649
Mar 19, 2017 at 16:48
• @feersum Not quite, the problem statement is to print out the code of the previous answer without hardcoding it.
– user42649
Mar 19, 2017 at 16:49
• That doesn't make sense. Mar 19, 2017 at 18:52
• @feersum How so? The general idea is to generate the previous answer without hardcoding it (because that would be trivial), so it's kinda like a kolmogorov challenge in some sense...
– user42649
Mar 19, 2017 at 18:54
• What does "hardcoding" mean to you? Please give a definition. Mar 19, 2017 at 18:57
• @feersum In my definition, "hardcoding" means that you just put "print" and then the exact text you want printed.
– user42649
Mar 19, 2017 at 18:59
• We usually use "hardcoding" to refer to an answer that exploits a limited input range to avoid performaing an expected algorithm, e.g. for a Fibonacci question where the input is at most 20, writing a list of 20 Fibonacci numbers in the code. Here the task is not associated with any calculation at all. Mar 19, 2017 at 19:05
• – user42649
Mar 19, 2017 at 19:06