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Questions tagged [restricted-source]

Imposes a restriction on the source code used to solve the challenge, for example, having no numbers in the source code.

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628 votes
333 answers

Produce the number 2014 without any numbers in your source code

Note to challenge writers as per meta consensus: This question was well-received when it was posted, but challenges like this, asking answerers to Do X without using Y are likely to be poorly received....
Joe Z.'s user avatar
  • 35k
272 votes
147 answers

Without using numbers, get the highest salary you can. But don't exaggerate!

As I'm applying for some jobs whose job advert doesn't state the salary, I imagined a particularly evil interviewer that would give the candidate the possibility to decide their own salary "...
Nicola Sap's user avatar
  • 3,685
235 votes
30 answers


You have been hired for your tech knowledge as a Secret Agent's sidekick to ensure that the good guy can get his job done and the world can be saved. This is your last mission before retiring with a ...
Averroes's user avatar
  • 4,107
169 votes
73 answers

How high can you count?

Challenge: Your task is to write as many programs / functions / snippets as you can, where each one outputs / prints / returns an integer. The first program must output the integer ...
Stewie Griffin's user avatar
153 votes
84 answers

Fewest (distinct) characters for Turing Completeness

Summary: For any given language, what is the smallest amount of unique characters for your language to be Turing-Complete? Challenge: For any language of your choice, find the smallest subset of ...
Julian Lachniet's user avatar
137 votes
148 answers

Obfuscated Hello World

Create the shortest possible obfuscated program that displays the text "Hello World". In order to be considered an obfuscated program, it must meet at least two of the following requirements: Does ...
Kevin Brown-Silva's user avatar
123 votes
95 answers

ASCII's 95 Characters...95 Movie Quotes

Update: The winner has been decided, but the challenge is not over! Finally, nearly 3 months after the question first started, someone has remained the last answerer for more than a week! ...
Calvin's Hobbies's user avatar
120 votes
19 answers

"Hello, World!" in zero lines of code

NPM's sloc is a moderately popular tool for counting source lines of code in a file. The tool will attempt to strip out both single and multiline comments and count the remaining lines in order to get ...
Sisyphus's user avatar
  • 14.8k
118 votes
76 answers

I'm a palindrome. Are you?

There have been a couple of previous attempts to ask this question, but neither conforms to modern standards on this site. Per discussion on Meta, I'm reposting it in a way that allows for fair ...
user avatar
106 votes
65 answers

Find an Illegal String

The challenge is to find a string of characters that cannot appear in any legal program in your programming language of choice. That includes comments, strings, or other "non-executable" parts. ...
nneonneo's user avatar
  • 12.3k
95 votes
36 answers

Eww, those bytes are gross

Write a program or function that, when given a string, filters out as many distinct bytes as it can and returns the cleaned string. However, since your program hates them, none of these bytes can be ...
Jo King's user avatar
  • 47.2k
93 votes
23 answers

Programming a Pristine World

Let's define a pristine program as a program that does not have any errors itself but will error if you modify it by removing any contiguous substring of \$N\$ characters, where \$1 \le N < \text{...
Calvin's Hobbies's user avatar
93 votes
20 answers

Pristine and Unique Code Bowling

Your challenge is simple: write as long of a pristine program as possible in the language of your choice using only unique bytes. (The full definition of a pristine program, copied from that link, is ...
praosylen's user avatar
  • 1,505
90 votes
108 answers

Hello World 0.0!

source: Dilbert, September 8, 1992 I'm hoping to add a new twist on the classic "Hello World!" program. Code a program that outputs Hello World! without: String/...
zzzzBov's user avatar
  • 3,274
86 votes
219 answers

The Letter A without A

Your task is to display the letter "A" alone, without anything else, except any form of trailing newlines if you cannot avoid them, doing so in a program and/or snippet. Code that returns (instead of ...
Buffer Over Read's user avatar
84 votes
42 answers

Non-discriminating Programming

We say a string is non-discriminating if each of the string's characters appears the same number of times and at least twice. Examples "aa!1 1 !a !1" is non-...
Laikoni's user avatar
  • 26.2k
83 votes
132 answers

Loop without 'looping' [closed]

A question similar to this has been asked a couple of years ago, but this one is even trickier. The challenge is simple. Write a program (in your language of choice) that repeatedly executes code ...
CailinP's user avatar
  • 1,043
79 votes
70 answers

Hello world! with limited character repetition

In a language of your choice, write a program that exactly outputs the characters Hello world! followed by a newline. The code: should not use any character more ...
Josh's user avatar
  • 2,761
75 votes
191 answers

Output your Score!

Challenge: The concept is simple enough: write a full program to output its own code golf score! Output should only be the byte count of your program and a trailing ...
X1M4L's user avatar
  • 1,836
75 votes
122 answers

Print the alphabet without using each vowel

Inspiration: in 1939, a man named Ernest Vincent Wright wrote a novel called Gadsby without using the letter 'e'. Your task is to write a set of (up to 5) programs in any language (which has a text-...
shamp00's user avatar
  • 1,261
74 votes
94 answers


Write a program that produces an output such that: At least three distinct characters appear. The number of occurrences of each character is a multiple of 3. For example, ...
darrylyeo's user avatar
  • 7,897
73 votes
155 answers

Print X without X (cop's thread)

This is the cop's thread of a cops-and-robbers challenge. You can view the robber's thread here A pretty common beginner style question is to print some string, but there's a catch! You need to do it ...
Wheat Wizard's user avatar
  • 98.8k
73 votes
84 answers

No strings (or numbers) attached

If you like this, consider participating in: The Official Dyalog APL 2016 Year Game The monthly Dyalog APL 2017 Code Golf Challenge Make 12 snippets/expressions, in the same language, that result in ...
Adám's user avatar
  • 30.4k
73 votes
29 answers

2016 Time Capsule String: How Versatile Is Your Language?

About a year ago on Dec 31, 2015, I had the idea that: We should make a time capsule string. Everybody gets to add one character and next new years we'll see who can make the best program out of all ...
Calvin's Hobbies's user avatar
72 votes
24 answers

Tweetable hash function challenge

In this code-challenge you will write a hash function in 140 bytes1 or less of source code. The hash function must take an ASCII string as input, and return a 24-bit unsigned integer ([0, 224-1]) as ...
orlp's user avatar
  • 39.1k
70 votes
170 answers

Print 0 to 100 without 1-9 characters

Print integers 0 to 100 (inclusive) without using characters 123456789 in your code. Separator of numbers can be comma or white space (by default <blank>, <...
user avatar
67 votes
20 answers

Just repeat yourself

Write a program that outputs Do not repeat yourself! Your program code must respect the following constraints : its length must be an even number each ...
Arnaud's user avatar
  • 8,533
66 votes
11 answers

Only Even Bytes

The scenario Lately you have been noticing some strange behavior with your favorite text editor. At first it seemed that it was ignoring random characters in your code when writing to disk. After a ...
Wheat Wizard's user avatar
  • 98.8k
65 votes
20 answers

Hash collision: "NO" means "YES"

This Code Golf was inspired by the recent Daily WTF article You Can't Handle the True!, which features a string comparison written as: ...
dan04's user avatar
  • 6,571
64 votes
63 answers

Write lines in detention

Introduction Bad news guys - you got detention. Your English teacher doesn't understand this site and wants you to "stop doing math on your digital dohickeys, this is English class!" She ...
hmatt1's user avatar
  • 3,466
61 votes
36 answers

Print the phrase "And she said, 'But that's his.'" using only the alphabet

Print the phrase And she said, 'But that's his.' using only the following characters: ...
Blue-Maned Hawk's user avatar
61 votes
31 answers

Output the text "Code Bowling"

Code-Bowling You've been hired by Brunswick Bowling to create a simple program to output the text Code Bowling on their monitors. This company is worth a pretty ...
Albert Renshaw's user avatar
60 votes
60 answers

Print every printable ASCII character without using it

In a programming language of your choice, write 95 programs, each of which outputs a different one of the 95 printable ASCII characters without that character occurring anywhere in the program. For ...
Calvin's Hobbies's user avatar
58 votes
19 answers

Write the whole of the holed using the unholed

The ASCII characters from decimal code 33 to 126 are: !"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~ ...
Calvin's Hobbies's user avatar
57 votes
169 answers

Output programming language name

Challenge: In the programming language of your choice, take no input and output your programming language's name. Fair enough, right? Restrictions: You can't use any character that is included in ...
Offtkp's user avatar
  • 3,062
56 votes
45 answers

All Your Base Are Belong To Us (Restricted)

Input must not be required, and output must read "All your base are belong to us". Restrictions No external resources. Plus a minimum of two of the ...
Eliseo D'Annunzio's user avatar
56 votes
36 answers

Conway's Monster

This challenge is in honor of mathematician John Conway who passed away April 11, 2020 due to COVID-19. He was famous for coming up with the Game of Life cellular automaton and many other mathematical ...
Calvin's Hobbies's user avatar
55 votes
92 answers

yes is 91 lines long

yes, from coreutils, is 91 lines long. Many of them are comments, but that is still WAY too long. Edit from September 2019: the source file grew over the past five ...
Ramon Snir's user avatar
55 votes
20 answers

Exit Code Golfing

Inspired by this default for IO. The Task Write a program that, given an input integer x between 0 and 255, crashes with exit code ...
Addison Crump's user avatar
55 votes
24 answers

Significant Whitespace

We define whitespace to be any of the three characters, tab (0x09), newline (0x0A) or space (0x20). For this challenge, you're to write two programs or functions in the same programming language, ...
Martin Ender's user avatar
54 votes
7 answers

Duct tape can fix Mother's Day

Based on the Duct tape can fix anything question, that was too broad, with very similar rules. Only this time the objective is very specific: The challenge Your mission is to make a program that ...
Dennis Jaheruddin's user avatar
54 votes
32 answers

Does it Lead or Follow?

In this challenge you are to write a program or function, that takes a string as input and outputs one of two possible values. We will call one of these values truthy and one falsy. They do not need ...
Wheat Wizard's user avatar
  • 98.8k
54 votes
2 answers

JSF**k with only 5 symbols?

This is not a challenge but a question, I figured it was on topic because of Non-challenge questions that are related to solving programming puzzles or a particular type of challenge are also on ...
Jens Renders's user avatar
  • 1,588
53 votes
53 answers

Print all ASCII alphanumeric characters without using them

Challenge Print the following characters: abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890 The catch is that you may not use any one of them in ...
anna328p's user avatar
  • 6,396
50 votes
66 answers

Divide a number by 3 without using *, /, +, -, % operators [closed]

Quoting this question on SO (Spoiler alert!): This question has been asked in an Oracle interview. How would you divide a number by 3 without using *, /, +, -, %, operators? The number ...
Gaffi's user avatar
  • 3,687
50 votes
5 answers

Multiply with restricted operations

There's a 500 rep unofficial bounty for beating the current best answer. Goal Your goal is to multiply two numbers using only a very limited set of arithmetic operations and variable assignment. ...
xnor's user avatar
  • 145k
49 votes
90 answers

Hack into a Lottery

You've recently made an account on a dodgy gambling site, where for a fee of 25 dollars, they will pay you back a random amount between 0 and 50 dollars. After getting around 5 dollars twice, you ...
colsw's user avatar
  • 3,367
49 votes
24 answers

A Chiral Puzzle

A shape is chiral if no amount of rotation can make it look like it's mirror image. In this puzzle we will be writing chiral computer programs. For this puzzle we will think of a program as a ...
Wheat Wizard's user avatar
  • 98.8k
49 votes
67 answers

Depalindromize this string!

Given a palindrome generated according to this challenge, depalindromize it. Test cases ...
Oliver Ni's user avatar
  • 10.6k
48 votes
17 answers

Determine whether a number is 2017-friable without primes in your source code

Out of all the years I've been making this challenge, 2017 is the first year that's been a prime number. So the question will be about prime numbers and their properties. Your task is to produce a ...
Joe Z.'s user avatar
  • 35k

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