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.

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Answer 1

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. . .

Answer 2

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 code-golf, 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 ?

Answer 3

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 popularity-contest, 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?

Answer 4

The only differences that matter

cops-and-robbers

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.)

Answer 5

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.

Answer 6

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?

Answer 7

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 code-golf 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."

Answer 8

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}

Answer 9

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 code-golf, so the code with the fewest bytes wins.

Related OEIS sequence

code-golf number

Answer 10

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

Answer 11

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

game-of-life

meta post about on topicness

Answer 12

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

---

Answer 13

Prelude:

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

Challenge:

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

Scoring/rules:

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

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

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

Example:

Printr, score 4:

print("r")

This program prints "r" then quits.

Answer 14

Print number of possible values of X if:

code-golf

• 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

Answer 15

[please suggest a name]

code-golfgraph-theorypath-finding

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.

Your code should output the path of the shortest way to go from the start to the final node.

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 code-golf rules apply.

Answer 16

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 code-golf 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

Tags: code-golf random number

Answer 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

Answer 18

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

Input

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

Answer 19

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)

Answer 20

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)

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This is code-golf, so standard rules & loopholes apply.

Answer 21

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

Answer 22

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.

Answer 23

Digitless digits

code-challenge restricted-source number

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 code-challenge 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.

Answer 24

You should log out code-golf

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In the programming language of your choice, log off the currently logged in user.

Rules and clarifications:

• After running the program the user should be taken to the login screen of the appropriate operating system, where they can re-login
• You can assume that no programs are running that would block the logout process with popups
• Solutions that just restart the computer to get to the login page are not allowed
• Always specify which OS / architecture / environment your code runs on
• Standard loopholes are forbidden

This is code-golf, so the lowest amount of bytes wins

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Sandbox questions:

• I'm unsure how to discourage answers where logout is achieved by expecting the code to be called from bash using "exec", or other solutions where logout is not actually initiated by the program, but by the caller process
• Do we have a tag for architecture dependent questions?

Answer 25

Google search result short summary

string fastest-code search

Intro

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

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

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

Task

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

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

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

Example

Given this webpage content:

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

and these searched words:

calls, sessions, internet

the program should return:

sessions include Internet telephone calls

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

Rules

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

Challenge

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

Answer 26

It's 42!

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

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

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

f(n)=9/2(n^2)−17(n)+29/2

Because f(6) = 42

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

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

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

Good Luck!

Answer 27

The Mnemonic Major System

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

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

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

Challenge

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

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

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

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

This is code golf, so the shortest solution wins.

Example Input and Output

758
golf, kale fee, key leaf

0142710
strengths, suitor nugget saw, seat run key tease

2362185
unimaginatively, gnome gin devil, enmesh native lie

Answer 28

Print the Previous Program

answer-chainingcode-challenge

Specifications:

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

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

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

0-byte submissions are not allowed.

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

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

Answer 29

Display Haftseen table items - in Persian/Arabic characters

Theme : Jalali New Year 1397

Main Goal : Displaying non-ASCII characters correctly

Introduction

A typical Haftseen table consists 7 items which their names start with س (pronounced like S) and some additional items. It is set few days before the new year's day and it's kept till end of new year's holiday.

Challenge

Your program/function should display exactly 7 items from the list below :

سبزه
سرکه
سکه
سیب
سنبل
سمنو
سماق
سیر
سنجد

with right alignment, right to left typing, in an Arabic-compatible font, with each word displayed correctly, and a non-alphabetical character (,.- =+~?,newline etc) between each 2 words. The list must be displayed in a window, in terminal or similar.

Answer 30

Code - Decode

Cops:

Your task is to write a program or functon wich otuputs encrypted alphabetic input. The same program or function has to be used to encrypt and decrypt messages as the case of ROT13

You have to post in your answer:

1. Languaje and length of your program
2. The encrypted output of the input "CODE GOLF"
3. Two more examples of crypted - unencrypted strings

Example:

Bash, 30 chars

1. "CODE GOLF" <=> "PBQR TBYS"
2. "SHA" <=> "FUN"
3. "Why did the chicken cross the road? Gb trg gb gur bgure fvqr!" <=> "Jul qvq gur puvpxra pebff gur ebnq? To get to the other side!"

You may post your program code an decpription of your crypting algorithm once is considered safe. Shortest uncracked answer wins.

Example:

tr '[A-Za-z]' '[N-ZA-Mn-za-m]'

This bash command crypts and decrypts messages shifting each letter 13 positions in the alphabet.

Robbers:

Your task is to write a program or function wich otuputs encrypted alphabetic input. The same program or function has to be used to encrypt and decrypt messages as the case of ROT13

Your code has to pass test cases posted on one of the COPS post. The user who cracks most wins.

Extra bonus if your code cracks more than one answer.

cops-and-robberscryptographyencryption