Sandbox for Proposed Challenges

Question

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.

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Answer 1

Popularly print the input

popularity-contest

Goal

Write a program or function in a language of your choice that takes input and outputs that exact input.

Specifications

• Your program/function should output the exact input in any reasonable way.
• Your program does not have to end after printing the input. It may end up in an infinite loop if you wish, as long as that loop doesn't output any extraneous characters.

Winner

The winning answer will be the one that has the highest score. Voters should look for answers that use an unique way to print the input, have a special source code or use neat language features.

Answer 2

Make a Login Screen

Challenge: make code that asks the user to enter a username and password. The username and password should be hard coded, but they must not be visible: you cannot have the entire username or the entire password in plain text in the code. Both the username and the password must be 8 characters long. Upon the incorrect username or password, some error should be displayed. It would be good if there are multiple "accounts" that would display different text on login. The password field should not be visible (Only asterisks or something).

This is Code-Golf, Shortest answer wins.

Standard loopholes are forbidden.

Answer 3

Of numbers of letters

there is something special the number 4. When spelled in English the word 'four' uses exactly 4 letters. I wonder whether there are further such numbers Your task is to identify whether there exist further such numbers and output them in any human readable format. To make this more of a challenge you can do the task in any regional Language of your choice (Say Russian or Portuguese or Spanish or Mandarin or Hindi etc.).

The Best entry will be selected by the most number of such numbers regardless of language used

Best of Luck

Answer 4

No strings code bowling

I created this challenege idea with @redwolfprograms. In the challenge, you would create the longest program possible (code-bowling) it can do anything, but it cannot:

• Contain any strings, or quotation marks/apostrophes/backticks
• Contain the same alphanumeric byte more than twice
• Conatin the same non alphanumeric byte more than three times

Answer 5

[Posted, but reference kept]

Given a function with boolean inputs a₁, ..., a_n and a boolean output, output an array of numbers 0 to n satisfying:

For each item in the truth value, if (from the array you output, we repeatedly remove two adjacent numbers x and y satisfying that, for each integer n between x+0.5 and y+0.5, a_n=1), we can get an empty result array iff the given function's output is 1. You can assume the result exist.

Sample input:

a[1] a[2] result
0    0    0
0    1    0
1    0    0
1    1    1

Sample output: 0 2

Sample input:

a[1] a[2] result
0    0    0
0    1    1
1    0    1
1    1    1

Sample output: 0 1 2 0 1 2

Sample input:

a[1] a[2] result
0    0    1
0    1    1
1    0    1
1    1    1

Sample output: (empty)

shortest code win, but optimizing running time and result length is encouraged(I won't accept but I may upvote)

You may check your answer here

Answer 6

Write a function that takes compares each pair of adjacent items and swaps them if they are in the wrong order. The pass through the list is repeated until no swaps are needed, which indicates that the list is sorted.

Static visualization of bubble sort and a gif explanation.

^{The steps go from left to right. At each stage, an exchange is made. The darkest color has the most value and finds its final place (bottom) first.}

---

The rules

• The function must take a list of integers that shall be sorted (less than 20 elements)

• The function must print each step of the sort.

• Yes, built-in Bubble sort algorithms are permitted.

• No, you can not assume only positive integers or unique integers.

• It's code-golf so the shortest code wins!

---

Test cases

input list
5 4 3 1 2
1 2 3 5 4
11 4 2 1 5

---

Optional

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

---

Note

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

^{This is not a duplicate of Bubble sorting in progress.}

^{Thanks to @Erik the Outgolfer for encouraging me to post my idea in the sandbox.}

code-golfbubblesorting

Answer 7

Once, I thought of this. Rules:

1: You must make a fractal that looks like the specified thing.

2: One thing per round.

3: Algorithms are rated by two scores: Resemblance and Compactness. The one that gets the highest scores wins!

4: Only I can tell what thing must be made.

5: Only one entry per user. Do not plagiarize.

6: One may code in anything they wish.

7: Have fun!

Round 1: Squidward's head!

Answer 8

This question is a simplified description of the requirement described at Permutations to the nines

---

Given input integer (minimum) where the first digit is always 1 and the adjacent digits are increasing in value, e.g.,

12

123

1234

12345

with the ability to handle up to the integer

123456789

where the maximum integer is always the input integer in reverse order, e.g.,

21

321

4321

54321

987654321

Task

Return a list (array) of each number between the input minimum and maximum integer which satisfies three conditions

1. the resulting integer list item includes only the individual numbers comprising the input number
2. the resulting integer list item does not contain any duplicate individual digits
3. the resulting integer list item is greater than the preceding integer list item and not greater than a following integer in the list

Test cases

Valid list items

12 -> [21] // done

123 -> [132,213,231,213,312,321] // done

Invalid list items

12345 -> 12344 // contains duplicate digits in whole number

123456789 -> 13256789 // not the next integer by increasing numeric value order

123456789 -> 987654322 // greater than maximum integer and duplicate digits

Winning criteria

The algorithm which uses the least amount of operations to compute the complete resulting list of items.

Examples

123 -> 123+5+4=132 // two mathematical computations

123 -> 123+9=132 // one mathematical computation (winning criteria)

(@JoKing suggested fastest-algorithm tag; math and code-challenge tags are also applicable)

Answer 9

All numeric substrings

code-golf

I like numbers. Really, really, like numbers. If you give me a string with numerals in it, I want to get all the numbers out of it that I can.

Input:

A string.

Output:

Every numeric substring, in any order, but only one of each. Numeric here means anything with Unicode General Category Nd (because I'm no xenophobe).

I/O

Any reasonable format. But languages that don't allow for multibyte-character I/O should use some numeric or other representation.

Test cases

(input → one ordering of the correct output)

• 1212 → [1212, 121, 212, 12, 21, 1, 2]
• 123٤٥6 ‪→ [1, 2, 3, ٤,‪ ٥, 6, 12, 23, 3٤,‪ ٤٥,‪ ٥6,‪ 123, 23٤,‪ 3٤٥,‪ ٤٥6,‪ 123٤,‪ 23٤٥,‪ 3٤٥6,‪ 123٤٥,‪ 23٤٥6,‪ 123٤٥6]‪
• 12t45 → [1, 2, 4, 5, 12, 45]
• abc → []

Answer 10

Fastest prime printer up to 500,000,000 with gapes

---

Write a program that takes no input and prints the first 26,355,867 prime numbers, from 2 to 499,999,993 inclusively. Or in other words, print all the prime numbers smaller the 500,000,000.

The fastest code wins!

Since it will take a long time to print all the numbers, print only every 26355 primes starting with 2 separated by a new line. So the output should look like this:

2
304417
648391
1007681
1376449
1752323
2133689
2520983
2910797
3304633
3702269

The output should not be hardcoded, or there is no fun in it.

The results will be tested on my machine, so please also output in the last line how long it took to run the program and give me some instructions about how to run it locally. I will then share the last line output with you that should contain the time it took to run.

Here is my machine system specs, note that it's Windows.

Answer 11

Mystery Numbers Challenge math

Here are some sample inputs and outputs:

IO

Test 1

Input: 102
Output: 10404 1061208 14002414191924244276669361796022272

Test 2

Input: 10
Output: 100 100000

Test 3

Input: 50
Output: 2500 312500000 312500000

BONUS

If there are two inputs, here are the corresponding inputs and outputs:

Test B1

Input:

50
12

Output: 144 248832 248832

Test B1

Input:

2310
9

Output: 81 729 59049 4782969 31381059609

Notes

If you pass all bonuses too, feel free to third your score. Also add a * to the end.

Answer 12

Make a search engine!

code-golf

Background

You are now the first employee of DuckDuckGoogle, a company founded by a Google employee and a DuckDuckGo employee! They have a new vision for search engine! But obviously, they need to make a search engine first! However, they are bad programmers (nobody knows how they were even hired at DuckDuckGo and Google!). So you are assigned the task of making a search engine.

Search engines

There are three parts to a search engine, a web crawler, an indexer, and a searcher.

The web crawler takes a link, and saves the page and stores the page data (the HTML code). It then looks for links in the page and visits those webpages and does the same. It will continue to do this until there are no more links left.

The web indexer will take the text from each page, take each word, and add it to a dictionary of words and the pages it is associated with. If the word is already in the dictionary, it adds the page as a value of that word that is found in the page. For example, lets say www.example.com/index.html contains the text "hello. thanks! goodbye." and the ww.example.com/index.html is linked to www.example.com/hello.html with the. text "hello. goodbye." The crawler would extract the text from the index.html, and find hello.html, and extract the text from hello.html. The indexer would make a dictionary like this:

dictionary ={"hello.": ["www.example.com/index.html","ww.example.com/hello.html"], "goodbye.":["www.example.com/index.html","ww.example.com/hello.html"], "thanks!": ["ww.example.com/index.html"]}

The simplest part of the search engine is the searcher, or retriever. It simply retrieves the value for the search term (i.e. the list of pages the search term is found in) and prints it. That is the final result of the program. So if the search term is "hello.", the program will print ["www.example.com/index.html","ww.example.com/hello.html"]

Now, here is the difficult part. You must take into account punctuation. So "hello" returns the same as "hello." Also the search engine should be case-insensitive. So "Hello" is the same as "hello", which, as we said, is the same as "hello." which was ["www.example.com/index.html","ww.example.com/hello.html"]

Challenge

The challenge is to write a search engine in the least number of bytes as possible. Why? Because your bosses have decided to use 90% of the one hard drive they have (budget problems!) for the Holy Grail part of their project and you only get 10%.

Rules

1. The input is the "seed", a url at which the crawler should start at, and also the search term.
2. The output is a list of webpage urls where the search term is found.
3. The program cannot use builtins for a search engine or even a crawler (or related, like a scraper or spider library).
4. No need to worry about Javascript at all. Assume that the pages will not have Javascript.
5. The webpages are assumed to have HTML 4.0.1 Strict.

Testing

I am pretty sure people know how search engines work. So I will only include two testcases. You can use the websites in the testcases for testing purposes as well.

> "https://www.udacity.com/cs101x/index.html" "crawl"
["https://www.udacity.com/cs101x/index.html","https://www.udacity.com/cs101x/crawling.html"]

> "https://www.udacity.com/cs101x/urank/index.html" "hummus"
["https://www.udacity.com/cs101x/urank/index.html","https://www.udacity.com/cs101x/urank/hummus.html","https://www.udacity.com/cs101x/urank/arsenic.html","https://www.udacity.com/cs101x/urank/kathleen.html","https://www.udacity.com/cs101x/urank/nickel.html","https://www.udacity.com/cs101x/urank/zinc.html"]

Answer 13

Calculate Hello World!

popularity-contest hello-world underhanded

Your goal is to calculate the simple string "hello world" or any other variant.

Rules

• You may not use the characters in this set (inside your code): hHeElLoOwW rRdD!, in any form (character codes, hex codes, etc. not allowed) [only applies for direct use].
• Your program may not take any input from any source.
• Your program may only print hello world or any other variant to standard output (for your language). Again, it may not print anything else.
• Standard loopholes apply (to clarify, they are not forbidden).
• This challenge is underhanded.
• Your program may not use any built-in string of printable characters (for example, string.printable in Python).
• I recommend you be creative.

Remember, this is popularity-contest! Have fun!

Answer 14

Letter Grade Challenge

Create a program that allows the user to input an int between 1 and 100, then grades that number based on standard US letter grades, printing the grade character as a result. Please use Java for this challenge, and like usual code golf challenges, the smallest answer (bytes) wins. For example, if input is 90, then you display A.

Answer 15

Shortest Possible 240 Sided Die Program: Using No Constant Greater than 6

code-golf

Have you ever played Yahtzee with a 240-sided die? No, probably not. Anyway, I came up with the idea of a 240-sided die program, but to make it hard, you cannot use a constant with an absolute value greater than 6. For example, randInt(1,240) wouldn't work. The chances of any number 1-240 must be completely equal, and using expressions that represent numbers with an absolute value larger than 240 is not allowed. For example, randInt(1,4*6*2*5) is against the rules, since 4*6*2*5 evaluates to 240. Standard loopholes prohibited, and you're code golfing.

Answer 16

I recently made a language called bit, and your challenge is to create a valid program that takes 2 numbers from STDIN, and outputs the sum of them. You may assume the numbers are no more than 5 digits, and your output doesn't need to be more than 5 digits long

Bit Specification

You can find the specification and an interpreter at the GitHub repo

Answer 17

Count up to N without math or inbuilds

Idea:

The challenge is the following: count from 0 up to N without using mathematical operations or other (counting, list or whatever) inbuilds. You handle the incoming number N as a string on which you can't apply mathematical operations like addition or substraction for example. Also don't use list things like print [0..N] or something other inbuilt of your language. Counting inside arrays, for example at index x+1 or something like that to get position after another is allowed. But you must not apply any (mathematical) operations on the numbers between 0 and N itself.

Think that you are like a small child and don't know anything about maths. You only know: after 0 comes 1, after 1 comes 2 ... after 8 comes 9 and after 9 comes 0 and you have to "increment" the number in front of it.

Examples:

• So after the number 9 (with leading, but not outwritten zero) comes, you write zero and place the number 1 in front of it for 10.
• For 19 you write 0 and "increment" the number in front to the next one, making it 20.
• For 399 you do: last 9 goes to zero, 9 in front goes to 0 too and the 3 goes to 4, making it 400.

Task:

Write a function or program which takes N via the way you want to as its input.
Output the numbers from 0 up to N (element after element or once as a list)
Important: use a seperator as 01234567891011 will become unreadable with larger numbers

Test Case:

Taking a string of seperated numbers and your seperator, you can check your answer here.

Ah, and also don't forget that this is code-golf, so shortest answer in bytes will win. Also, all standard loophole rules and so on apply (you should know from all the other challenges!)

---

Sandbox

I hope this challenge has never been here, I did not found it while searching trough the already asked challenges (maybe I did not found it because I did not knew the correct english words to search for because english is not my first language). Thank you already in advance for helping to improve this challenge.

Tags:

counting, code-golf

Answer 18

Smallest code to import in G++

Given some head files that need to import, return the shortest code to do so.

1. You are allowed to access include/
2. You should consider both #include <xxx> and #include "xxx"(used in e.g. backward/hash_set #include "backward_warning.h"), but not #import (std don't use #import)

Sample input ['string']

Sample output #import<map>

Related

1. What more assumption necessary? (#if don't effect imported heads?)
2. Time limit necessary?

code-golf parsing c++

Answer 19

Merge two code in two languages into a polyglot.

E.g. If you choose C & Python 3, you can merge

main(){puts("a");}

and

print(6)

into

#define print(x) main(){puts("a");}
print(6)

popularity-contest (for it's hard to have a score on language difficulty, optimizy, etc.)

Answer 20

code-challenge

Delete or a file disapear as fast as possible!

Requirements to participate:

• have a HDD hard drive, witch you will use to compete
• Use Windows (version 7 or more recent) for this challenge.

Assume that you already know the file path. no input needed.

You can use any language you want for this challenge, but you will need to explain the logic in your code.

You will delete a 2GB file.

How do you win?

You win this challenge by creating a piece of code that can delete a file in the OS as fast as possible, the winner is the one with less time to delete a file.

Answer 21

Worst language Ever

Let's find out the worst language.

Make a program that does anything that is shortest.

The worst language would be the longest of all.

I'll go with C first.

C (gcc), 15 bytes

f(){puts("1");}

Try it online!

It prints 1.

It does print something and it is the shortest code.

Swift 4, 8 bytes

print(2)

Try it online!

It prints 2. It does print something that is shortest.

Answer 22

Write the worst Hello World program you can [popularity-contest] [super rough]

Who needs conventions? Write the most terrible Hello World program you can think of. Inefficiency, spaghetti code, you name it. Add a few gotos here and there to spice it up. Write code that has gone against everything you've ever been taught.

Be creative. This isn't about obfuscation: it's about bad code quality. Try making up your own ways of writing inefficient or unadaptable code. Have fun!

Answer 23

Divisibility by 4

Your job is to write a program that checks divisibility of an integer by 4.

Restrictions:

You can't use:

• modulo
• binary shift/rotates
• Divisions

You must instead do it like a HUMAN DOES by checking the last 2 digits and output a truthy value when is divisible and a falsey when not.

Non-printable characters; golfing-dedicated, whitespace and esoteric languages are forbidden.

The winner will be the code that has less characters, where white space doesn't count (tabs, spaces and newlines).