Sandbox for Proposed Challenges

Question

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".

Answer 1

Stop the dance!

Your sister was at the hospital, but now she's fine, awfully, you lost a day of work, one of your most important days.

You work at your local television, and they have a contest, called "Stop the dance!", what is it about?: People is dancing, they have a big screen in the wall, while it says "Dance!", they have to dance, if it says "Stop!", they must stop, if you move, you lose.

You don't have internet at the studio, so you use some strange offline data sharing method. The day you weren't there, another programmer came, such a silly programmer! He made a "Reciever" program, basically, gets data, processes data and prints data in the Big Screen Wall.

The programmer was bored, so he made a way to get data, well, you don't know what way he choose! (Author comment: Let's assume he made all the possible ways. Cya.) Now you have to make a sender program, in any language, that sends data to that program using the protocol specified under this section.

You are an expert code golfer, so you decide that you must make the shortest code possible. (Another author comment: Any lang is allowed. Cya.)

How did I came out with this idea?

Having a shower, my friend...

Your task

You must make the shortest (and winner) code possible, that sends data to the reciever, using this protocol:

The reciever must recieve:

$displaytext:"<text here>";$instnm:<integer here>;

$displaytext corresponds to what it is going to be displayed on the Big Screen Wall.

$instnm corresponds to the number of the instruction, the count of things displayed, starts from 1.

Your program may take an input, and send the data, in any way (except the ones in Rules) to the Reciever. Remember there's no internet.

The winner will be the user with shortest bytes of code.

Rules

As a good code golfer, you may not:

• You can't use program arguments to send the data.
• It must be an application.
• If you apply for the bonus, mind you have to make both programs, if not, just the sender.
• The string you have to send it has to be STRICT, no different ones, if not, unvalid answer. (I decided to call that "Strict JASON Protocol", get the joke?)

Bonus

You can make the reciever program, and you get -1 byte. Not much, but k. (In bytes, you must not decrement your byte result, you must do: "n Bytes + Bonus")

Example Input and Output

Input:

From Sender program:

Dance! or Stop!

Protocol:

Inbetween both commands

$displaytext:"Dance!";$instnm:5

Output:

In Reciever program:

Dance! (9) or Stop! (187)

Overall objective:

Send data between two programs, without internet connection.

Edit: i can't post an example answer, because then i can give ideas of how to do this codegolf/puzzle, while the ideas are limited, i'm finding for the creativity of the user.

Answer 2

Biggest single character

This challenge is simple, its like the busy-beaver challenges we've had before where the goal is to produce the biggest output one can. But in this one, you can only use one character in your code.

You get no input, your code has to be a single character (not byte), and the person with the largest output in byte wins, ties broken by posting time.

Answer 3

Alphabetization 101 (popularity contest)

Your task is to use all 52 letters of both the uppercase and lowercase alphabet, ONCE and ONCE only, and make a program.

You are free to use any other ASCII character more than once, or use a letter of the alphabet more than once if it's required for the language to function.

Meta:

• Not sure if this has been done before.
• Any questions regarding the task?

Answer 4

Why did I come to Sandbox?

I have a very specific challenge, and I wanted to see if it was too specific.

The challenge is to output "Valdosta ACM" using the shortest number of characters with the BrainF**k programming language.

I've noticed it isn't the norm to specify a programming language on this domain, so I've come here to get feedback on whether or not this is acceptable.

---

Introduction

As a challenge to the members of my local Association for Computing Machinery(ACM) chapter, I asked them to produce the shortest Brainf**k code that would output "Valdosta ACM".

This was a very fun challenge for all of our members, and we got very competitive! I was impressed with the solutions turned in, but I wondered if it was possible to beat our best solution. Surely it's possible, but who could do it?

Challenge

Output the string "Valdosta ACM".

Stipulations:

• Use only the Brainf**k programming language (you can test your code here)

• No input can be accepted by your program

• Your program must halt

• The space in the string must be ASCII character #032.

These are the ASCII values of each character, as they appear in the string, for convenience:

 086 097 108 100 111 115 116 097 032 065 067 077

The winner is determined by the shortest code, by character count.

Example Input and Output

Input:

NO input is allowed

Output:

Valdosta ACM

Answer 5

The FitnessGram™ Code Golf Test

Same concept and rules to the well-known Rick Astley post a while back, only instead of using samples of various sizes, sample length is limited to what number sample it is. And different text for the program to write.
It's code golf, so standard loopholes apply, and fewest bytes wins.

Answer 6

Obfuscate your program

In this challenge, you must create a program which does something but you need to obfuscate it so that it becomes hard to understand (so don't explain it in your post).

It can accept anything as input and output anything.

Score

The shorter program (in bytes) which hasn't been understood wins.

Example

Can you guess what does this code calculate?

var t=1e5,s=t/1e4,n=s*0.1,i=n*s*7.5,r=!true,b=1,t='01'.split('').map(c=>parseInt(c)).concat(Array(i).join('.').split('.').map(m=>{a=r+b;(r=b)&&(b=a);return a})),t=t.join('').length,b=s,t=r,s=4+NaN;

Rules

• You should say what language you used
• You must not use any obfuscation tool

Answer 7

"01_firstHole" Challenge for Performance Golf

First there was code golf. Now, there is Performance Golf. FORE!

Motivations

This is a crowd-sourced approach to easier and better performance troubleshooting. Performance problems are everywhere, so java technicians need access to easy-to-use diagnostic tools at every step of the SDLC.

How to play?

1. Start by installing the live demonstrations of Java Performance Problems in this repo.

2. Pick one of the six holes of golf to play. You can do this by picking one of the six numbered folders in the repo. This particular codegolf.stackexchange.com challenge is for the 01_firstHole.

3. One at a time, run the 'a' load test and the 'b' load test for the hole you selected. The a & b tests are two different implementations of the same REST/SOA service. See the 'installing' link, above, for how to run the tests.

4. Compare the performance of the two tests, a & b. Which has better response time / throughput?

5. Using the least amount of tooling/instrumentation, identify the performance problem of the slower test. Hook it up your self and run the tests.

6. At codegolf.stackexchange.com, there is one "Stack Exchange Challenge" for each hole of golf. Post the following two things for your solution to that challenge:

   • Post a description of the tools/techniques you used to detect the performance problem. Must be detailed enough so that others can reproduce your work. Performance golf always compares two different loads -- a & b. The solution must identify the inefficient code in the slower of the two examples. It must also show the absence of that inefficient processing in the faster of the two examples.
   • Tally the number of strokes for your approach, using the "Scorecard" below. All solutions must specify the # of strokes incurred, and it must be specified in the answer heading/title.

7. Upvote the solutions that best identify the performance problem and have the fewest strokes (see Scorecard, below). Similar solutions on different platforms (Mac/Linux/MS-Win) deserve roughly the same number of upvotes.

Scorecard

This scorecard determines the approach with the least amount of tooling/instrumentation. Lowest score wins!

• 1 stroke if JVM restart is required to hook up your monitoring tool of choice.
• 1 stroke for any tool with any $$ licensing cost.
• 1 stroke for every separate install process. No strokes for JVM and pre-installed OS tools.
• 1 stroke for tools/techniques specific to a particular Database vendor. Ex: Oracle AWR report. Even ‘EXPLAIN PLAN’ solutions are proprietary.

Example One -- zero strokes :-D

This example does not use this github repo, but it will give you the general idea.

This solution to solving a high CPU problem would get lowest=best instrumentatin score: zero strokes. Only JVM and OS tools are used (thread dump and top -H). There are no tool license costs and a JVM restart was not required for the thread dump.

Example Two -- 3 strokes :-(

This example also does not use this github repo, but it will give you the general idea of what we mean by the best troubleshooting with the least tooling/instrumentation.

A modern, commercial profiler (YourKit, JProfiler, etc...) would easily solve the high CPU problem in example 1. But look how many strokes (1+1+1=4!) are taken off with this approach: * 1 stroke because a JVM restart is required to hook up the tool * 1 stroke because there are licensing costs. * 1 stroke to install profiling the tool

Answer 8

Make a Fork Bomb code-golf

^{under construction, please constructively (no pun intended) criticize}

Create a program which forks itself at twice and exits, or forks itself once and idles. Whether it continues forever or exits is your choice. Forks can be OS forks or simply a command to relaunch the program.

Rules

• No spoon bombs allowed, please.
• Don't make any assumptions about the location of the program.

---

Bash, 10 chars

./$0|./$0&

Acts as a standard punching bag for other solutions.

---

Microsoft Windows Batch file, 5 chars

 %0|%0

Anybody who beats this one gets a million internet points. (and maybe a bounty)

Answer 9

Stump The Golfing Languages

This is the seed of an idea. I'm unclear on the details that might make it work.

I want people to submit answers in the form of a program in a "normal" language (defined how?), such that reproducing its functionality in a golfing language isn't much smaller. That is, I want to find the algorithms that Jelly and Pyth and Matl and such are not optimized for.

I would appreciate suggestions on how to make this work. Maybe cops and robbers? Maybe each entry just contains two programs, and comments are given to help golf the smaller one?

Answer 10

Draw "Stack Exchange"

Stack Exchange has many site (159) and It has a logotype too. Anyway, In this challenge you'll need to draw Stack Exchange in the most shortest way.

This is a code-golf. challenge.

Rules

1. Have fun!
2. You've to draw Stack Exchange, you can't use Paint or something like that, you can't use libraries.

Answer 11

Open the browser, polyglot edition. polyglotcode-challenge

Your job is to open a browser window of the default browser to https://codegolf.stackexchange.com in as many languages as possible.

Your code must open the browser itself, and cannot rely on an open one.

Rules

• Versions of the same language are considered a single language

Answer 12

Mad lads!

Inspired by the paper calculator episode of Numberphile.

Your challenge in this puzzle is to take in two two-bit (0-3) numbers and output the sum of the two numbers... using ordinary household objects.

Some possibilities of how this can be done:
Dominoes
Paper
Marbles
music box (+ some helpers..)

Input:

input must always be involving two sets of two-bit integers, which can be represented by anything you like, so long as the cardinality of the representations is the same.

Output:

The output should be a single 3-bit integer which represents the addition of the two inputs.

Rules:

• your device cannot have the capability to connect to the internet in any way (sorry, this also disqualifies carrier pigeons). Your device must also not be able to perform this function alone (eg a calculator).
• It must be somewhat original. put your own twist on it!
• though, your entry can be alive (does your dog add??), so long as your entry is not in discomfort.
• Pictures are required for each entry to show how it works. videos would be better, but aren't required!
• The sole function of your machine does not have to be adding, it can do other things as well. This means that older projects that may serve a slightly different function are welcome, so long as they meet the rules stated above.
• Your device can be as simple or as complex as you like, so long as it doesn't get to a point where it's completely esoteric.

Judging:

You will be judged based on ease of use, ease of understanding, as well as originality! This means that entries should be easily explained, used, and be unique in some way.

This is a popularity-contest, so the most upvotes wins! good luck!

Answer 13

99 selttob fo reeb no eht llaw popularity-conteststring

I teb ev'uoy lla draeh tuoba eht doog 'lo 99 selttob fo reeb no eht llaw. Llew ti os sneppah taht I emoc morf na evitanretla esrevinu - eht esrevinu erehw ew etirw gnihtyreve ni esrever! Ew peek eht snoitisop fo lanigiro hguoht. Siht osla snaem reporp noitazilatipac fo tsrif (ekil rettel ni siht txet). Ruoy egnellahc si ot etirw a margorp taht stuptuo eht lausu 99 selttob fo reeb no eht llaw, tub ni esrever (ni ruo egaugnal uoy dluow llac ti 99 bottles of beer on the wall). Siht si a ytiralupop tsetnoc, os teg evitaerc dna yrt ot sserpmi eht dworc. Doog kcul!

I bet you've all heard about the good ol' 99 bottles of beer on the wall. Well it so happens that I come from an alternative universe - the universe where we write everything in reverse! We keep the positions of original though. This also means proper capitalization of first letter(like in this text). Your challenge is to write a program that outputs the usual 99 bottles of beer on the wall, but in reverse (in our language you would call it 99 selttob fo reeb no eht llaw). This is a popularity contest, so get creative and try to impress the crowd. Good luck!

Elpmas fo derised tuptuo:

Sample of desired output:

---

99 selttob fo reeb no eht llaw, 99 selttob fo reeb. Ekat eno nwod dna ssap ti dnuora, 89 selttob fo reeb no eht llaw.

89 selttob fo reeb no eht llaw, 89 selttob fo reeb. Ekat eno nwod dna ssap ti dnuora, 79 selttob fo reeb no eht llaw.

...

1 elttob fo reeb no eht llaw, 1 elttob fo reeb. Ekat eno nwod dna ssap ti dnuora, on erom selttob fo reeb no eht llaw.

On erom selttob fo reeb no eht llaw, on erom selttob fo reeb. Og ot eht erots dna yub emos erom, 99 selttob fo reeb no eht llaw.

Answer 14

Best n out of 2n - 1

Challenge:

This one should be relatively simple. Output this exact text:

Best [n] out of [2n - 1].

given n as an input.

Input:

Just the integer n, can be from stdin or as an argument. n will always be greater than 0.

Output:

The exact text above. Trailing spaces/newlines are allowed.

Rules:

This is code-golf, so shortest code in bytes wins. Standard loopholes are forbidden.

Meta:

Is this too simple? What other tags should be included, string?

Answer 15

Google Home / Amazon Echo - Turing complete?

code-challenge

Your challenge is to try to make a turing machine based on Google Home and Amazon Echo, see this video.

You must describe how to set up the machine, and how to give it input.

You must also describe a program for integer addition. It should compute 1+1 to be 2, 200+55 = 255, 200+56 = 0, and so on for all other combinations of 2 8-bit integers.

Answer 16

Make a Simple GUI application

I have made a simple glade layout. The chalenge is to remake it in as few bytes as possible.

The glade file:

<?xml version="1.0" encoding="UTF-8"?>
<!-- Generated with glade 3.20.0 -->
<interface>
  <requires lib="gtk+" version="3.20"/>
  <object class="GtkApplicationWindow">
    <property name="can_focus">False</property>
    <property name="title" translatable="yes">Remake me!</property>
    <child>
      <object class="GtkBox">
        <property name="visible">True</property>
        <property name="can_focus">False</property>
        <property name="orientation">vertical</property>
        <child>
          <object class="GtkButton">
            <property name="label" translatable="yes">hello</property>
            <property name="visible">True</property>
            <property name="can_focus">True</property>
            <property name="receives_default">True</property>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">0</property>
          </packing>
        </child>
        <child>
          <object class="GtkLabel">
            <property name="visible">True</property>
            <property name="can_focus">False</property>
            <property name="label" translatable="yes">world</property>
          </object>
          <packing>
            <property name="expand">False</property>
            <property name="fill">True</property>
            <property name="position">1</property>
          </packing>
        </child>
      </object>
    </child>
    <child>
      <placeholder/>
    </child>
  </object>
</interface>

Answer 17

Rock Paper Scissors Lizard Spock

This game is from The Big Bang Theory, an extended version of the classic Rock Paper Scissors game.

Objective

To create a full program that I can run to play Rock Paper Scissors Lizard Spock against an "AI". The opponent ("AI") will pseudo-randomly choose their option after receiving user input.

The program must be run with user input of the following;

| Input     | Meaning   |
|-------    |---------- |
| R         | Rock      |
| P         | Paper     |
| S         | Scissors  |
| L         | Lizard    |
| SP        | Spock     |

The game is played with the following rules that Sheldon tells us;

Scissors cuts Paper

Paper covers Rock

Rock crushes Lizard

Lizard poisons Spock

Spock smashes Scissors

Scissors decapitates Lizard

Lizard eats Paper

Paper disproves Spock

Spock vaporises Rock

Rock crushes Scissors

Once you've taken user input, psuedo-randomly chosen the AIs option, you must output either "Player wins (<<user_input>> vs <<ai_input>>)" or "AI wins (<<user_input>> vs <<ai_input>>)". In the event of a tie (both the user and AI choose the same options), you must output "It's a tie"

Sample Runs

//Player chooses Scissors (S)
//AI chooses Paper (P)
$ php -f rpslsp.php S
Player wins (S vs P)

//Player chooses Spock (SP)
//AI chooses (R)
$ php -f rsplsp.php SP
Player wins (SP vs R)

//Player chooses Lizard (L)
//AI chooses Scissors (S)
$ php -f rsplsp.php L
AI wins (L vs S)

//Player chooses Lizard (L)
//AI chooses Lizard (L)
$ php -f rsplsp.php L
It's a tie

Rules

• Standard loopholes apply.
• The computer must choose an input at random (pseudo random) so that on each program run, the AI chooses (in a perfect world) a different input and that each input has the same percentage of being chosen.

---

This is code-golf so the shortest code in bytes wins.

Answer 18

Fastest Compiling Fibonacci Sequence compiler fibonacci fastest-compiling

Your task is to create a program which takes one numerical input and outputs all numbers in the Fibonacci sequence up to that point. However, you will not be scored on its bytecount or how many upvotes it gets. You will be scored on how quickly the compiler can compile it.

---

Rules

• Of course, compiled languages are the only languages allowed.
• All answers are tested on an Amazon EC2 instance with an Intel Xeon at 2.4GHz, about 1 GB of ram, and Amazon Linux installed. You can time your program on an equivalent machine, but I will compare results.
• Your program is allowed to produce warnings when compiled, but it should work properly when run.
• Compile time is tested with the time command, and "real" time is used for the final score.
• If I need to comment the amount of time you took, you should add it to your answer.
• Of course, standard loopholes are strictly disallowed.

---

This is fastest-compiling, so may the cleverest optimization win and the best programmer prosper...

Answer 19

Be typically flexible efficiently

code-challenge

Write a short function that returns outputs of different types in a non-boring way. If L is the length of your code and T is the number of different types returned, your score is (T−1)/L. The highest score wins.

• The function must take exactly one argument and be deterministic, i.e., the output depends only on the input.

• Obviously your programming language must have an official notion of type, by which each object has a unique, clearly identified type. Typically this would manifest in a type or typeof function returning an object’s type. Also, it must obviously allow functions to have differently typed returns.
  If there are many separate typing systems in your language, you have to pick one (conforming with the above) and stick to it.

• The function must not employ any conditional constructs or other language features whose primary purpose is to handle logic, such as if statements, loops, or logical conjunctions. (Obviously, employed predefined functions need not adhere to this.)

• All inputs needed to produce the outputs used for scoring as well as any elements of container structures must adhere to the following:

  • They are all of the same type.
  • If they are functions or otherwise callable (and actually called in your program), they must consistently return objects of the same type.
  • They must not be classes, type identifiers, or similar.
  • If they are strings, they are treated (with respect to these rules) as any obvious interpretation of them as code, class names, or similar.
  • If they are containers themselves, their elements must adhere to these rules when taken together.

  So, e.g., in Python the following are invalid:

  a = lambda i: [ 0, 0., [], {}, (0), {0} ][i]
  b = lambda i: [ int, float, list, dict, tuple, set ][i]()
  c = lambda i: [ [0], [0.], [[]], [{}], [(0)], [{0}] ][i][0]
  d = eval   # using "0", "0.", "[]", "{}", … as input
  e = lambda i: eval( ["0","0.","[]","{}","(0)","{0}"][i] )
  

  This also applies to containers generated during by the function during its execution. (Obviously, this does not apply to such objects if used internally by employed predefined functions.)

---

Valid (ungolfed) example

Python:

def f(i):
    return sum([2.][0:i])

For this we have:

f(0) == 0
type(f(0)) == int
f(1) == 2.0
type(f(1)) == float

This makes use of the fact that the sum of an empty iterable (like [2.][0:0]) is 0.

---

Sandbox questions

• I am pondering whether I should replace a portion of the rules with a catch-all like:

  If whatever trick you use to acquire n types of output can be used to obtain n+1 types of output, it is invalid. (If n+1 just doesn’t work because n is the total number of types in your language, this doesn’t count either.)

  Obviously, this would lessen the chance of any boring loopholes, but it would also be more likely to be subject to interpretation. Do you think this is a good idea?

• Did I miss any obvious loopholes that would make this challenge boring?

• This challenge was mainly done with Python in mind, but I seen no reason why it should not extend to other programming languages (with a suitable typing system). Are there any obvious pitfalls with other languages that I should consider?

• Are there any other appropriate tags for the question?

Answer 20

Puzzle:

• Make a program that draws the following figure line by line.

• Your program should wait for one-second(it can be longer, just has to be a noticable difference) after drawing each line.

• Your program can only draw line by line (you cannot jump to another point or re-draw over a line)

• Given a positive integer n, produce an art image of the below drawing

• The angle measures should always be the same (regardless of n's value)

• However, each line's length should be 150*n pixels

• You only need to account for when n = 1, n = 2, n = 3

Specifications:

if n=1:

• length = 150 pixels

if n=2:

• length = 300 pixels

if n=3

• length = 450 pixels

.

.

Answering - Name the language you used followed by its bytes

Example:

Java (swing), 500 bytes

.

Scoring

• This is code golf. Lowest score (bytes) wins.
• standard loopholes are forbidden.

Good luck!

Answer 21

I have seen many a trivial answer in jelly, so i wish to propose:

Challenge: A non-trivial answer

• Input two strings
• If the two strings are integers and are equal, output a truthy value.
• Otherwise, output a falsy value.

Clarifications

• You may receive non-integer inputs.

• You will never receive an integer that is outside the bounds [-2³¹, 2³¹). Rules

• Standard loopholes are disallowed.

Scoring:

• This is not your standard code-golf
• the winner person who posts the longest program.
• an entry is invalidated if someone posts a shorter program in the same language.

Answer 22

Golf This Question

Your program should output to STDOUT the full text of this question as it appears on your screen, so no HTML. This includes the title and the body. Please do not edit this question whatsoever so-as to keep it the same for all programs.

No reading the text from a file or the internet

This is code-golf, so the shortest code wins!

Sandbox Is this a good question? Is there anything I should clarify?

Answer 23

Find the min swaps for order one powerset for a List

The question it is write one powerset function and one sort function tha minimize the swaps for doing one order with this compare function on powerset of the List A

cmp(a,b) -- a and b are subset of the list A
    if sizeof a > sizeof b then (swap a and b; return)
    if sizeof a < sizeof b than return
    for i in 1..(sizeof a) repeat
         for j in 1..(sizeof A) repeat
               if a[i]==A[j] then return
               if b[i]==A[j] then (swap a and b; return)

the result of this compare function on the sets wuold be the follow:

(15) -> powSet([1,2,3])
   (15)  [[],[1],[2],[3],[1,2],[1,3],[2,3],[1,2,3]]
                                                      Type: List List Any
(16) -> powSet([3,2,1])
   (16)  [[],[3],[2],[1],[3,2],[3,1],[2,1],[3,2,1]]
                                                      Type: List List Any

note that order depend not from the number element, but on the position on the start List A=[1,2,3]

(17) -> powSet([1,2,3,4,5,6])
   (17)
   [[], [1], [2], [3], [4], [5], [6], [1,2], [1,3], [1,4], [1,5], [1,6], [2,3],
    [2,4], [2,5], [2,6], [3,4], [3,5], [3,6], [4,5], [4,6], [5,6], [1,2,3],
    [1,2,4], [1,2,5], [1,2,6], [1,3,4], [1,3,5], [1,3,6], [1,4,5], [1,4,6],
    [1,5,6], [2,3,4], [2,3,5], [2,3,6], [2,4,5], [2,4,6], [2,5,6], [3,4,5],
    [3,4,6], [3,5,6], [4,5,6], [1,2,3,4], [1,2,3,5], [1,2,3,6], [1,2,4,5],
    [1,2,4,6], [1,2,5,6], [1,3,4,5], [1,3,4,6], [1,3,5,6], [1,4,5,6],
    [2,3,4,5], [2,3,4,6], [2,3,5,6], [2,4,5,6], [3,4,5,6], [1,2,3,4,5],
    [1,2,3,4,6], [1,2,3,5,6], [1,2,4,5,6], [1,3,4,5,6], [2,3,4,5,6],
    [1,2,3,4,5,6]]
                                                      Type: List List Any

Win the one that minimize the swaps for order the powerset of the follow list

[1],[1,2],[1,2,3],[1,2,3,4],[1,2,3,4,5],[1,2,3,4,5,6]

Patterns match for composed expression

If we have one math expression B(x) [that mean in B appear x] [math expression is one expression where appear only symbols for function and operator of mathematics that are ok for type and compose ] Find the max lengt subexpression g(x) of B contain x such that

B(x)=f(g(x))

And f(y) and g(x) are both math expression.

Find Max for a function in one interval

R is the set of real numbers. Is given a function f:A->R from set A (⊆ R) to the R, continue and derivable in one close interval

 [a, b]⊆A

Write the shortest program for find

 max{f(x): x in [a,b]}

knowing the function f(x) derivable in the interval [a,b]. The solution has to be correct at last until the V digit after the float point, and for all functions f that has 10 value max in which f'(x)= 0 in [a, b]. codegolf tag

On Riemann Zeta function domain

If Zeta:C->C is the Riemann Zeta function, we give the set:

 W={b: 0<b<100 and Re(Zeta(0.5+i*b))=-Im(Zeta(0.5+i*b))}

Where Re() return the real part of its argument, and Im() return the imaginary part of its argument.

It is requested to calculate one approximation of each element of W; this means here all b in float numbers with b in 0..100 such way

  abs(Re(Zeta(0.5+i*b))+Im(Zeta(0.5+i*b)))<0.0001 

at last, to put all together in a array or list or set of float.

One can note that the below set of zeros for the Riemann function is a subset of above W set.

 {b: 0<b<100 and Zeta(0.5+i*b)=0}

Some test

Some numbers b approssimation to solution of equation

Re(Zeta(0.5+i*x))+Im(Zeta(0.5+i*x))=0 

the ones that are approssimation to solution of equation Zeta(0.5+i*x)=0 too

[14.134725, 21.022039, 30.424876, 32.935061, 37.58617815, 40.918719, 43.327073, 48.00515, 49.773832]

the ones not approssimation to solution of equation Zeta(0.5+i*x)=0 too

[12.458493623791109003, 24.351346882420215577, 28.716611773969890307]

The code more short in bytes that find all these approssimations of element of the set W wins...

Code golf tag

Answer 24

Shortest code to draw a png from stdin

Rules :

• You’re free to use any image library you want as long as the image library is designed in the same language as your answer.
• The image should be displayed in an Xorg or wayland window or a console framebuffer.
  If you’re displaying to a window, you don’t need to create any windows control (in that case the programs ends with CTRL+C).
• The stdin stream doesn’t eof. so the only way to get the image size is to parse png data. Once the image had been displayed, /dev/stdin should be closed.
• Your answer shouldn’t crash on random data.

The answer using the fewest bytes wins !

Answer 25

Hack Stack!

Your challenge is to create a code snippet in javascript that will upvote your answer when run. This should not be possible, but maybe it is. We'll see!

Rules

Standard Loopholes are not allowed.

You should not auto-downvote other answers.

Do not manually upvote any ansewer, please!

The first one to write code that also accepts the answer when it is run by me will remain accepted.

For discussion:

Is this even a valid challenge?

Answer 26

Feliz navidad, prospero año y felicidad

code-golf kolmogorov-complexity

So christmas is comming and carols are on the radio all day. Jose Feliciano's Feliz Navidad song is a good example of this. Your task is to print the entire (and repetitive) song.

Lyrics:

Feliz navidad
Feliz navidad
Feliz navidad, prospero año y felicidad

Feliz navidad
Feliz navidad
Feliz navidad, prospero año y felicidad

I want to wish you a merry Christmas
I want to wish you a merry Christmas
I want to wish you a merry Christmas from the bottom of my heart

I want to wish you a merry Christmas
I want to wish you a merry Christmas
I want to wish you a merry Christmas from the bottom of my heart

Feliz navidad
Feliz navidad
Feliz navidad, prospero año y felicidad
A-ha!

Feliz navidad
Feliz navidad
Feliz navidad, prospero año y felicidad

I want to wish you a merry Christmas
I want to wish you a merry Christmas
I want to wish you a merry Christmas from the bottom of my heart

I want to wish you a merry Christmas
I want to wish you a merry Christmas
I want to wish you a merry Christmas from the bottom of my heart

Feliz navidad
Feliz navidad
Feliz navidad, prospero año y felicidad

Feliz navidad
Feliz navidad
Feliz navidad, prospero año y felicidad

I want to wish you a merry Christmas
I want to wish you a merry Christmas
I want to wish you a merry Christmas from the bottom of my heart

I want to wish you a merry Christmas
I want to wish you a merry Christmas
I want to wish you a merry Christmas from the bottom of my heart

Feliz navidad
Feliz navidad
Feliz navidad, prospero año y felicidad 

RULES:

• Default loopholes are forbidden.
• Default I/O.
• Programs or functions are acceptable.
• You MUST include the ñ character in the año word.
• You can print it in lowercase, uppercase or sentence case.
• Shortest code in bytes wins!

Answer 27

Ultimate crackpot

In minimum number of ASCII bytes, write a plain text "physics research article" in English that scores each item in The Crackpot Index at least once.

_{I'm not sure if such thing is on-topic here or on the Puzzling.}

Answer 28

Same code, different work

Write a code in a language that do these few things:

1. Input a positive integer n, check whether it's a prime. (2 -> true, 5 -> true, 8 -> false)
2. Input an integer n>1, output an array with fewest positive prime as element, where the sum of the array is n. (2 -> [2], 5 -> [5], 6 -> [3, 3], 8 -> [3, 5] or [5, 3])
3. Input an integer n, output sum(n mod i, for i=1 to n). (2 -> 0, 5 -> 4, 8 -> 8)

Your code should theoretically solve all legal n, but in practive up to 1000 is enough

Shortest code in bytes win.

code-golf

Answer 29

Write a program who return the current month.

The Rules

• The result needs to be correct even if the program is run in the future.
• It's code-golf so the shortest code wins!

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Optional

Add an interpreter so the submission can be tested. It is allowed to write this interpreter yourself for a previously unimplemented language.

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^{It's my first code-golf idea I'm fully open to improving it with more experienced users.}

code-golf date

Answer 30

Output Infinity (updated v2)

code-golf kolmogorov-complexity

Challenge

Output the following infinity symbol:

         ∞∞infinity                         ∞infinity                   
     infinity∞∞infinity                 infinity∞∞infinity              
   infinity∞∞∞∞∞∞∞infinity           infinity∞∞∞∞∞∞∞infinity            
  infinity        ∞∞infinity      ∞∞∞∞∞infinity        ∞∞∞∞∞∞∞          
 ∞∞∞∞∞                 ∞∞∞∞∞∞∞  ∞∞∞infinity               ∞∞∞∞∞         
 ∞∞∞                      ∞∞∞∞∞∞∞infinity                   ∞∞∞         
∞∞∞                         ∞∞infinity                       ∞∞∞        
∞∞∞                       ∞∞infinity                         ∞∞∞        
 ∞∞∞                    ∞∞∞∞∞∞infinity                      ∞∞∞         
 ∞∞∞∞∞               ∞∞∞infinity  ∞∞∞∞∞∞∞                 ∞∞∞∞∞         
  infinity       ∞∞∞∞∞infinity     ∞∞∞infinity        infinity          
    infinity∞∞∞∞∞∞∞infinity           infinity∞∞∞∞∞∞∞infinity           
      infinity∞∞infinity                infinity∞∞∞infinity             
           ∞infinity                        ∞∞∞infinity                 

Rules

• No input.
• Output can be given in any convenient format.
• Any number of trailing spaces at the end of each line is allowed.
• Any number of trailing new lines at the end of the shape is permitted.
• Either a full program or a function are acceptable. If a function, you can return the output rather than printing it.
• If possible, please include a link to an on-line testing environment so other people can try out your code!
• Standard loopholes are forbidden.
• This is code-golf so all usual golfing rules apply, and the shortest code (in bytes) wins.