# What is the Sandbox?

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

To post to the Sandbox, scroll to the bottom of this page or click on the "Add Proposal" link below, 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. 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, replace the post here with a link to the challenge and delete it.

See the Sandbox FAQ for more information on how to use the Sandbox.

## Get the Sandbox Viewer to view the sandbox more easily

To add an inline tag to a proposal use shortcut link syntax with a prefix: [tag:king-of-the-hill]

# Left and Right

Given an input string, in ASCII, output ")|]" as many times as the case-insensitive word "right" appears in input, and output "(|[" as many times as the case-insensitive word "left" appears in input. The order is irrelevant. If and only if no occurences of these words are in input, output "X|X". Spacing between items is optional

This is , less bytes is best

Test cases:

input -> output
RightRightighteftleft -> (|[ )|] )|], or some other ordering
this doesn't contain either word -> X|X
LEfT, LeFT, leFT, righT -> (|[ (|[ (|[ )|]
(|[ -> X|X


## 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. – Nathan Merrill Aug 16 '16 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. – Peter Taylor Aug 16 '16 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 – Destructible Lemon Aug 19 '16 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. – FryAmTheEggman Aug 20 '16 at 22:03
• Your code is also stylized. Does your code run properly? – Buffer Over Read Aug 20 '16 at 22:34
• @ColdGolf And do you think I'd stylize my post by hand? – gaazkam Aug 21 '16 at 2:13
• @FryAmTheEggman OK, thank you. I now see my challenge was pointless and won't post it to the main. – gaazkam Aug 21 '16 at 2:14
• Nothing is pointless: now you you know more and can come up with a better challenge! :) – FryAmTheEggman Aug 21 '16 at 2:17
• @ColdGolf OK you were right, I messed up the stylization. {'b', 'и'} - here is a bug. Sorry. – gaazkam Aug 21 '16 at 2:22
• @gaazkam Does your code, with the stylized цsiпg Sчstem;, run properly? – Buffer Over Read Aug 21 '16 at 2:39
• @ColdGolf I regard people of CodeGolf intelligent enough to find out they'd have to unstylize this code ^^ :) – gaazkam Aug 22 '16 at 7:11
• @gaazkam I see. – Buffer Over Read Aug 22 '16 at 17:34

# Enterprise Quality Code!

## Summary of this challenge

Print (to make it more fair when competing with another language changing the output method could be a trivial way to golf) the first N Prime numbers. Your score will be the sum of the byte counts of all entries which no one has been able to golf down (by removing one or more characters and rearrange the program). If you golf down someones program, post it as another submission.

You may not golf your own programs once submitted.

This is not a dupe because it significantly changes the scoring method. Writing code which allows a single byte to be golfed off will cost the whole of the score. Also as this is a challenge the winner is likely going to have high scores across a multitude of languages. It is likely that scores will be incredibly near 30k for each language. This limit allows a more interesting competition as it prevents submissions of exponentially large lengths.

### Back-story and explanation

At Pretty Good consultants there is a focus on writing "quality" verbose code that is sufficiently engineered. Your boss has decided to test you on your skills.

Consider the set of all programming languages in existence before the posting of this challenge. For this challenge there will technically be one individual "winner" in each language, however the boss will give a promotion accepted tick mark to only one answer based on your score.
The goal of this challenge is to receive an integer N strictly smaller than 2^16-1 and print the first N prime numbers (in less than 24 hours) separated by your platforms choice of new line. OEIS sequence A000040 in as many bytes as possible in as many languages as possible. However, note that others vying for the promotion will try to "help" you by golfing down your score.

Sample output for an input 11

2
3
5
7
11
13
17
19
23
29
31


## How to participate

Pick any language X, but please avoid selecting a language which is just another version or derivative of another answer. If there is no existing answer in language X than you will write a program (which must fit into a single post) that solves this challenge. The length in bytes of the source (in any reasonable preexisting textual encoding) will be added to your score. You must avoid using any unnecessary characters for reasons that will soon become apparent.

If language X already has been used to answer this question, then you must answer using any permutation of any proper subset of the characters used in the shortest answer (I.E take the shortest X answer and remove some (>=1) characters and optionally rearrange the resulting code). The previous holder of the shortest X answer will lose all of the bytes provided by his answer from his score, and the number of bytes of your submission will now be added to your score. The number of bytes golfed off gets "lost" forever.

Clarifications shamelessly lifted adapted from this challenge

### Rules for Languages

Languages used should be distinctly different. A language is different iff:

• It is not a different version of another language (Java 7, Java 8)
• They must not be derived from another language (Branf*** versus Alphf***)
• One language may not be a subset or superset or trivial of the other one (e.g. hq9+ versus hq9+b).

HQ9+ wouldnt be a language anyway, but please be judicious when selecting a language, if you have any clarifications on a language that may be significantly different from an existing answer please ping me and we can work it out.

• If anyone knows how to make a scoreboard for this I will be much obliged – Rohan Jhunjhunwala Aug 20 '16 at 17:28
• So the highest score wins, overall (from all your still-valid answers). And when you outgolf somebody, they lose their points, you gain your points, but do you get the points that they lost? – Rɪᴋᴇʀ Aug 20 '16 at 17:42
• @EasterlyIrk the way I had it planned out is that the amount of bytes golfed off is forever lost. I don't know if thats fair but that essentially prevents people from "profiting" off of ridiculous answers that were not fortified against being golfed. – Rohan Jhunjhunwala Aug 20 '16 at 17:49
• Yeah, that's what I figured. You might want to clarify that a bit though. I really like the idea. – Rɪᴋᴇʀ Aug 20 '16 at 17:52
• @EasterlyIrk clarifications added, let me know if this is ready for main – Rohan Jhunjhunwala Aug 20 '16 at 17:59
• It might be ready, but you should wait for somebody else to also give input. – Rɪᴋᴇʀ Aug 20 '16 at 18:01
• All right sounds good – Rohan Jhunjhunwala Aug 20 '16 at 18:04
• 1. So basically the accepted answer goes to the shortest answer in Unary? 2. The tags code-golf and code-bowling are mutually exclusive. This isn't really either. – Peter Taylor Aug 20 '16 at 19:49
• @PeterTaylor please read the whole thing. The answer must fit within 30k – Rohan Jhunjhunwala Aug 20 '16 at 20:02
• If someone can write a brainf*** program that is only about 6 chars long or so than they deserve the accept tick – Rohan Jhunjhunwala Aug 20 '16 at 20:03
• @RohanJhunjhunwala Golunar wins – Rɪᴋᴇʀ Aug 20 '16 at 22:07
• @EasterlyIrk lol thats actually just a compressed form of Brainf*** it probably wouldn't score that well – Rohan Jhunjhunwala Aug 20 '16 at 23:15
• @PeterTaylor essentially I restrict answers to fit in one post which means the best score for a single language is slightly under 30 characters – Rohan Jhunjhunwala Aug 20 '16 at 23:15
• I find the intro confusing. I didn't understand what the challenge is broadly about until reading to the end. Can you cleanly state the challenge at the beginning, and move the details later? – xnor Aug 21 '16 at 0:42
• @trichoplax the overall winner with the highest score summed up over all of their answer posts will receive the tick on their highest scored post. It doesn't really matter which post in particular (as long as it is a post of the winner) receives the tick, but it makes sense to tick off the highest scoring post. – Rohan Jhunjhunwala Aug 21 '16 at 12:44

### Alphabet ripple

You must print out this exact text:

abcdefghijklmnopqrstuvwxyzzyxwvutsrqponmlkjihgfedcba
abcdefghijklmnopqrstuvwxyyyyxwvutsrqponmlkjihgfedcba
abcdefghijklmnopqrstuvwxxxxxxwvutsrqponmlkjihgfedcba
abcdefghijklmnopqrstuvwwwwwwwwvutsrqponmlkjihgfedcba
abcdefghijklmnopqrstuvvvvvvvvvvutsrqponmlkjihgfedcba
abcdefghijklmnopqrstuuuuuuuuuuuutsrqponmlkjihgfedcba
abcdefghijklmnopqrsttttttttttttttsrqponmlkjihgfedcba
abcdefghijklmnopqrssssssssssssssssrqponmlkjihgfedcba
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 ._. – TuxCrafting Aug 21 '16 at 14:23
• Duplicate, too lazy to find. – Leaky Nun Aug 21 '16 at 14:27
• @LeakyNun you're too lazy to search through your own challenges...? – trichoplax Aug 21 '16 at 20:49
• @trichoplax I don't feel like wasting my time to search for the duplicate. – Leaky Nun Aug 21 '16 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... – trichoplax Aug 21 '16 at 21:15
• @LeakyNun, this Show tree rings age? – manatwork Aug 23 '16 at 10:50
• @LeakyNun what exactly is the duplicate? I'd like to know. – Conor O'Brien Aug 27 '16 at 16:39
• @ConorO'Brien this – Leaky Nun Aug 27 '16 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 – Rohan Jhunjhunwala Aug 30 '16 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. – Peter Taylor Aug 31 '16 at 7:52
• Golfing in ABBYY FineReader Engine has never been so exciting. – Andreï Kostyrka Aug 31 '16 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...) – wizzwizz4 Sep 1 '16 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" – Lamedonyx Sep 1 '16 at 8:45
• At the moment it's "who has the shortest program name". – wizzwizz4 Sep 1 '16 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. – Peter Taylor Sep 1 '16 at 11:42

Find all paths in a matrix maze.

A maze is represented as a two-dimensional array of 0s and 1s. Zero indicates a closed door and one indicates an open door. An example representation of maze is given below.

0100
0010
1101


to avoid loops input square matrix should not contain a square of once like

111      11
101  or  11
111


Write an application either in Java,C,C++,Python,C# or Javascript. It takes as input a maze(mxn array) and prints out all the possible ways out.

• No database should be used.

• Yes...Way out is any edge containing 1.

• Enter from any edges of the maze

• Exit from any edges of the maze

• Should not enter and exit from the same door

• Move can be one unit distance either top/bottom/left/right/diagonal

For the above maze, one possible way out is: [0,1] -> [1,2] -> [2,3] i.e you start at [0,1] and then move to [1,2] and then to [2,3]. There are other possible ways as you can see.

• Probable dupes: One, Two – Emigna Sep 8 '16 at 15:10
• Also, restricting challenges to specific languages are frowned upon. An objective winning criterion is also needed. – Emigna Sep 8 '16 at 15:10
• @Emigna, No Actually, here we need to find all the paths not the shortest path or straight path and here we can also traverse diagonal in the matrix. – Ali786 Sep 8 '16 at 15:15
• okay will add few more languages that I know so that I can evaluate ... – Ali786 Sep 8 '16 at 15:16
• 1. "Handle error cases like a production application" is not a clear requirement. Different production applications have different standards for how to handle errors. 2. "prints out all the possible ways out" runs into trouble when there's an infinite number, and I don't see any guarantee that there won't be loops. 3. The example doesn't make the input format very clear. What's the non-rectangular border for? 4. Path-finding with a trivial input format is definitely a dupe of at least one previous question. – Peter Taylor Sep 8 '16 at 15:31
• @PeterTaylor, I have modified my question, can you plz check once. – Ali786 Sep 8 '16 at 16:04

# 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 '16 at 17:05
• @tuskiomi No, it's open to all languages. – wizzwizz4 Sep 29 '16 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 '16 at 17:07
• @tuskiomi Thanks, will do. Give me 6 to 8 weeks... – wizzwizz4 Sep 29 '16 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. – Calvin's Hobbies Sep 29 '16 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 '16 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"? – wizzwizz4 Sep 30 '16 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. – Calvin's Hobbies Sep 30 '16 at 6:35
• @HelkaHomba Do you have suggestions as to which questions to change / remove / reword to stop it being bad subjective? – wizzwizz4 Sep 30 '16 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. – MD XF May 26 '17 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. – wizzwizz4 May 27 '17 at 8:06

# Quine tree

Inspired by that really weird quine challenge

For this challenge, you must construct a quine tree, which is a thing I made up, specifically an infinite binary tree.

How a quine tree works:

A quine tree has infinite nodes.

• Each node is associated with a program

• Let X, Y, Z, be the programming languages. This program is a polyglot in X and Y. In all but the root node, it is also a polyglot in Z. Note the

• see below for more details

• Each node has exactly two children

• Every node but the root has a parent. Their parent has the node as a child (obviously).

Programs:

• When a node's program is run in X, it produces the program of the first child of that node.
• When run in Y, it produces the program of the second child of that node.
• The programs produced must be different (node foo's program, cannot have the same output in X and Y. This output must also be different than the nodes program).
• If not the root node, when run in Z, it produces the parent of the node.

## Example

Imagine that we have the (fake) programming languages Hello, World, and Foobaz. Say the root node is $QQ$QQ$;: • when run in Hello, perhaps it produces $QQ$QQ$;;
• When this is run with Hello again, perhaps produces $QQ$QQ$;;; • When this is run with World, perhaps produces $QQ$QQ$;;Q
• Both these programs must produce, run in Foobaz, $QQ$QQ$;; (Output of root node run in Hello) • when run in World, perhaps it produces $QQ$QQ$;Q
• When this is run with Hello, perhaps produces $QQ$QQ$;Q; • When this is run with World again, perhaps produces $QQ$QQ$;QQ
• Both these programs must produce, run in Foobaz, $QQ$QQ$;Q (Output of root node run in World) • Both these programs, run in Foobaz, must produce $QQ$QQ$; (root program).
• This seems like a really interesting challenge. I'm not sure how possible it is, though! Substitution languages like /// might be easiest to solve this in. – wizzwizz4 May 27 '17 at 8:20

# The only differences that matter

## Cops' task

Write two programs (or functions) A and B in the same version of the same programming language. They also should be called in the same way, meaning you can't write one program and one function. Each should accept an integer n and output the term n of a different integer sequence on OEIS.

You should reveal a substring of each of A and B. Call them PA and PB. If one instance of PA is replaced by PB from A, it should become B. That means every byte except the reveal part in A and B should be exactly the same. You also reveal the lengths of A and B, and the two OEIS sequences. You don't reveal the programming language you use.

Your answer is cracked if a robber finds two programs A' and B' that also print the elements in the two integer sequences respectively, where A' is no longer than A, and A' with one instance of PA replaced by PB is also B'. They don't have to be the same with your original A and B. And they don't have to be in the same programming language as yours, as long as they are in the same programming language themselves.

If your answer isn't cracked 7 days after you post the answer, you can reveal your language and the original A and B and mark the answer safe, and it will be immune to future crack. Your answer can still be cracked if you don't do it.

Your score is max(len(A)+len(PA)*5, len(B)+len(PB)*5). The safe answer posted before a certain date with the minimum score wins.

For example, if your two programs are The first program and The second program, you can reveal first and second. Your score is 18 + 6*5 = 48. And a robber can crack your answer by <<first>> <<second>> if they work. But you can also reveal first pro and second pro to prevent this crack.

Please post your answer using this template:

# <length of PA> / <length of A> bytes, <length of PB> / <length of B> bytes, score <score>, <open / safe / cracked>

Part of program A (outputing [<OEIS number>](<OEIS link>)):

<code of PA>

Part of program B (outputing [<OEIS number>](<OEIS link>)):

<code of PB>

<any other explanations>


## Robbers' task

(To do.)

• Do robbers have to produce the same program, or any program? – Nathan Merrill Oct 28 '16 at 14:47
• There are two tricky edge cases around character encodings which the question needs to address. 1. It talks about substrings of A and B, saying that every byte except the revealed ones must be the same. If A and B differ in one Unicode codepoint, such that in UTF-8 they differ in only one byte but it's part of a three-byte sequence, can I post just that one byte as PA/PB or must I post the three-byte sequence? (I.e. are the substrings operating on the bytes or on the codepoints?) – Peter Taylor Oct 28 '16 at 20:57
• 2. If my program is in APL using an 8-bit encoding, do robbers answering in a language other than APL have to have the same bytes in the part of their file corresponding to PA/PB or the same Unicode codepoints? – Peter Taylor Oct 28 '16 at 20:57
• @NathanMerrill Any program. – jimmy23013 Oct 28 '16 at 21:05
• @PeterTaylor I'm considering requiring every program to be in printable ASCII (and tabs and newlines), as some special characters effectively banned many languages. But I'm not sure about newlines, which have the \r problem. – jimmy23013 Oct 28 '16 at 21:09
• Maybe I'll just say \r\n is counted one byte in this challenge, and is interchangeable with \n. But the programs in one submission must use only \n or only \r\n. – jimmy23013 Oct 28 '16 at 21:13
• An example would make this easier to understand, – xnor Oct 29 '16 at 6:08
• I'm skeptical about having the programming language be a free variable. If a cop writes an answer using a verbose language, a robber can comment out all the visible parts and stuff a terse language answer into the cracks. – feersum Oct 29 '16 at 11:24
• @feersum But that's the whole point of all the requirements. If you comment out all the visible parts, both your programs usually should output the same thing. But I realized it's easy to have some workarounds in languages such as Befunge. I may try to find a way to ban them, or just abandon this post. – jimmy23013 Oct 31 '16 at 0:59

# Translation Polyglot

Your task is to write a program which runs in two distinct programming languages to translate text. Input should be translated between each language i.e. running your code in Code Language A translates from language 1 to 2, while running your code in Code Language B translates from language 2 to 1.

Rules:

• Code Languages must be distinct, two versions of the same language are disallowed
• Your code may be a full program or function
• Your code must take one string (or nearest equivalent) as input. Input may be user input, function arguments, or other reasonable form
• Output may be a function return, output to STDOUT, or other reasonable form. I do not care about trailing newlines or spaces
• Your code may translate from/to any language on the official language list on Wikipedia. List the languages in your answer
• To accomplish your goal, you may use prebuilt language tanslation dictionaries such as the ones found here.
• If you read your dictionary as an external file, only the code to read in the file (f = open("dictionary.txt", 'r') in Python) counts towards your byte count. If your dictionary is hardcoded in, only count the bytes required to make it syntatically valid code (s="word1_in_english word1_in_french ..." would be 4 (s="")). Essentially, do not include the dictionary as part of your submissions byte count.
• The dictionary you use must have been created before this post (including sandbox time). You may not modifiy the dictionary in any way.
• Any built-in translation tools are disallowed. Built-in dictionaries are ok, but whatever code used to import them into your code must be included in the byte count

This is code golf, so shortest answer in bytes wins.

• wait... Are you actually asking for machine translation? Seems very difficult. Haven't you ever seen bad translator? If it actually is machine translation, this won't work, because of the different resolution of the languages (like converting a jpg to a png and expecting the same quality back) – Destructible Lemon Nov 1 '16 at 4:11
• It's really just value lookup. I'm not asking people to to make their own dictionary, just use a pre-built and accept whatever it translates – wnnmaw Nov 1 '16 at 13:45
• But that doesn't really satisfy Language A produces output O from input I, while running in Language B produces output I from input O. – Destructible Lemon Nov 1 '16 at 22:04
• Ah, now I see the source of confusion. Updated text to require basic translation, not symmetric translation – wnnmaw Nov 2 '16 at 11:53
• Also I don't think translation is objective enough for code golf... – Destructible Lemon Nov 3 '16 at 5:30

# Three-way meta-quine polyglot code-golf

Produce a program A such that running it in language A produces Program B, and running program A in language B produces program C.

Program B, when run in language B produces Program A, and running program B in language A produces program C.

Program C, when run in language A or language B, prints "Wrong language!".

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!"


Your answer should use this template:

# Language A/Language B, {a bytes} + {b bytes} = {total bytes} bytes

Language A:

a code


Language B:

b code


Source:

# Language A/Language B, <a bytes> + <b bytes> = <total bytes> bytes

Language A:

a code

Language B:

b code


• None of these programs should take input.
• Different versions of the same language count DO NOT as different languages. - Languages A and B must be distinct.
• You must not read your own source code from a file. Programs may not be empty
• Standard loopholes apply.

This is , the smallest sum of the byte counts Program A and B wins.

• Downvote reason? – noɥʇʎԀʎzɐɹƆ Nov 8 '16 at 20:23
• It's probably not possible. I'll revert my downvote if you can find a solution within 24 hours of this comment. – MD XF Jun 7 '17 at 21:39

# 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. – Geobits Nov 17 '16 at 17:44
• Changed it to "The sequence, if infinite, must contain" blah blah blah – Gabriel Benamy Nov 17 '16 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." – Peter Taylor Nov 17 '16 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. – Gabriel Benamy Nov 17 '16 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) – Nathan Merrill Nov 17 '16 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. – Gabriel Benamy Nov 17 '16 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"? – Nathan Merrill Nov 17 '16 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. – Peter Taylor Nov 17 '16 at 19:22
• That's a good point. Is there any way to salvage this concept? – Gabriel Benamy Nov 17 '16 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. – FlipTack Nov 19 '16 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!" – noɥʇʎԀʎzɐɹƆ Nov 23 '16 at 23:38
• +1 this comment if you think the title should stay the same – noɥʇʎԀʎzɐɹƆ Nov 23 '16 at 23:38
• Reply to this question if you have a better title – noɥʇʎԀʎzɐɹƆ Nov 23 '16 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... – ETHproductions Nov 24 '16 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 │
└───┴───┴────┴─────┴─────┴────┴───┘


### Task

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

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? – acrolith Dec 2 '16 at 22:14
• @daHugLenny fewest characters, should have known to include that – george Dec 2 '16 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 '16 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 – george Dec 3 '16 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? – AdmBorkBork Dec 8 '16 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 '16 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 '16 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. – ETHproductions Dec 9 '16 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. – noɥʇʎԀʎzɐɹƆ Dec 10 '16 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 '16 at 14:40
• @ais523 I'll do a true palindrome one then a convenient palindrome one later, perhaps? (also 11 then means ?) – noɥʇʎԀʎzɐɹƆ Dec 10 '16 at 14:44
• @ais523 When those challenges have been run elsewhere, they have? – noɥʇʎԀʎzɐɹƆ Dec 10 '16 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 '16 at 15:27

# 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. – Stewie Griffin Jan 16 '17 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. – Stewie Griffin Jan 16 '17 at 19:52
• Those were actually different puzzles, sorry! – endriklos977 Jan 17 '17 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. – Stewie Griffin Jan 17 '17 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 – user2428118 Jan 17 '17 at 9:35
• Not a duplicate. Though related, clearly not a duplicate. – Matthew Roh Jan 17 '17 at 10:32
• By the standards of this site, it is a duplicate. – Peter Taylor Jan 18 '17 at 11:48
• Proof of duplicate? – Matthew Roh Jan 18 '17 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. – Laikoni Jan 18 '17 at 11:53
• Okay, thanks for the suggestion. @Laikoni – Matthew Roh Jan 18 '17 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?" – trichoplax Jan 19 '17 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. – Matthew Roh Jan 19 '17 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. – trichoplax Jan 19 '17 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? – Gabriel Benamy Jan 19 '17 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. – trichoplax Jan 19 '17 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). – Peter Taylor Jan 19 '17 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. – Mario Jan 20 '17 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. – Mario Jan 20 '17 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. – Mario Jan 20 '17 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]. – Emigna Jan 20 '17 at 9:46
• @Emigna if you try my C# example it works for N=5. – Mario Jan 20 '17 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. – Peter Taylor Jan 20 '17 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. – trichoplax Jan 20 '17 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. – Mario Jan 20 '17 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. – Mario Jan 20 '17 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. – trichoplax Jan 20 '17 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. – FlipTack Jan 22 '17 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. – wizzwizz4 Jan 22 '17 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. – FlipTack Jan 22 '17 at 18:49
• It was to clarify for languages that need " at input. I'll change it. – user63571 Jan 22 '17 at 19:06
• Also whoever downvoted can you tell me why? I might be able to improve the question – user63571 Jan 22 '17 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 – Magic Octopus Urn Jan 23 '17 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!. – Magic Octopus Urn Jan 23 '17 at 19:52
• Thanks for the help – user63571 Jan 23 '17 at 20:24
• If you want to reply to someone, tag them - @JackBates – FlipTack Jan 23 '17 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 '17 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 '17 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 '17 at 20:30
• I found something that works! :) – user63571 Jan 25 '17 at 20:44
• Check rules number 2 and the examples – user63571 Jan 25 '17 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. – fəˈnɛtɪk Jan 25 '17 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 '17 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. – Peter Taylor Jan 25 '17 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 '17 at 23:09
• My point is precisely that rule 2 and the second example contradict the problem statement, which therefore needs fixing. – Peter Taylor Jan 25 '17 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 '17 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". – Peter Taylor Jan 26 '17 at 8:34
• What rules make it say "What I said earlier was a lie"? – user63571 Jan 26 '17 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 '17 at 19:03
• What's your point? Are you suggesting I change it in some way? – user63571 Jan 26 '17 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 '17 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? – MildlyMilquetoast Feb 3 '17 at 16:01
• @MistahFiggins On it – ckjbgames Feb 3 '17 at 16:26

# What in the heck just happened?

I want you to write a program that will bleep out the H-word, regardless of where it occurs, whether it is inside of another word or a stand-alone word, whether capitalized or not.

## Input and Output

The inputs and outputs of your program may be any of the following: an array of characters, a string, or any other standard data structure which does the job. However, the output must match the case of the input.

## Samples:

In the format of Input: Output
A Shell gas station : A Sheck gas station
Hell is a very bad place to be. : Heck is a very bad place to be.
Ella fell and Nelly dug a well. : Ella fell and Nelly dug a well.
Chellsea Thell bought shells. : Checksea Theck bought shecks.


Standard loopholes apply, and the entry submitted by [insert date here] with the lowest number of bytes as defined by the Meta will win.

• I can't say for sure, as I don't have an exact reference, but I'm pretty sure a simple find and replace challenge has been done before. – ATaco Feb 13 '17 at 0:19
• "Hell" and "heck" are both "H-words", so you need to be clearer. Also, I feel like this is a duplicate. Though these are milder swear words, I think someone did one with swear words in general and it got deleted. If you're going to make a find/replace challenge, it's simple enough to make it about something else. – mbomb007 Feb 13 '17 at 0:19
• Ah, I see. So, are you saying I should change what's being replaced or what my idea is? – Drew Christensen Feb 14 '17 at 0:50

# 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) {
echo \$i++;
}


# Meta questions

• Has this challenge already been done ? I feel like it's not a revolutionary idea and am afraid someone has thought about it before.
• Could you give me examples of "forbidden loopholes", as I don't really now all the esoteric programmation languages you guys are using.
• Finally, do you think it's a good challenge ? And if not, what could be done to improve it ? That's my first proposed challenge, so I'm aware there might be blatant errors or misses.
• Regarding loopholes, you can link to this: Loopholes that are forbidden by default – Emigna Feb 22 '17 at 10:38
• If you intend to ban "boring" answers, like predefined character classes you need to be very careful as writing a Do X without Y challenge can be very hard to get right. – Emigna Feb 22 '17 at 10:39
• Code-challenge doesn't provide an objective winning criteria by default so you need to explicitly specify one. – Emigna Feb 22 '17 at 10:40
• Thank you for your input @Emigna. I think most upvotes could be the winning criterion, since I don't want it to be a code-golf challenge. I'll edit and add the loopholes link. – roberto06 Feb 22 '17 at 10:45
• Related: Print all ASCII alphanumeric characters without using them, Print every printable ASCII character without using it. This challenge is in between those two, and I'm not sure if there's space for a third (because many answers are likely to end up similar to answer to one of those). – user62131 Feb 22 '17 at 10:47
• @ais523 I don't think the second example you're giving could be considered as a dupe, since only one character is forbidden for each execution. As for the first one, I see two major differences with my propose challenge : letters are allowed here, which would make it easier for submitters to create a "real" function, and this is not a code-golf challenge, which might reduce the numbers of answers written in esoteric languages such as Brainf**k. I hear what you're saying, but IMO, this challenge could find its space, as I'm really looking for readable and inventive solutions. – roberto06 Feb 22 '17 at 10:57
• Oh, I missed the victory condition. A "most upvotes" victory condition uses the popularity-contest tag, not code-challenge. Popularity contests historically tend not to do that well here, as a notable proportion of the site's userbase dislikes them (although many other users are fine with them). – user62131 Feb 22 '17 at 10:59
• The winning criterion could be something else, I set it to "most upvotes" because I supposed "The winner is whosever solution I find the most interesting" wouldn't have been a good criterion. I'm open to ideas though, what do you think could be an accurate and impartial victory condition (still, I'd rather not use "shortest code" as the criterion) ? – roberto06 Feb 22 '17 at 11:04
• "Inventivity" is not objective. The obvious way to do this in CJam neither uses prebuilt classes with all the digits nor any other standard loophole, is two characters long, and by virtue of being obvious is probably not "inventive". If you feel the need to try to forbid non-inventive answers, that suggests to me that you already know that the answer to "Is it a good challenge?" is "No, it's not". – Peter Taylor Feb 27 '17 at 14:38