Kolmogorov complexity, informally, is the amount of code it takes to produce a given string of text. When posting a challenge in this category, please make sure it adds something new to the challenges that already exist.

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11
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1answer
384 views

Two-zero-one-five puzzle

Background This puzzle is a variation on the four fours puzzle (itself the topic of a past question). Like that puzzle, the aim is to find mathematical expressions for different whole numbers, using ...
60
votes
21answers
5k views

Interpreting Fish (no, not that Fish)

Consider these five ASCII art sea creatures: Standard fish: ><> or <>< Speedy fish: >><> or <><< Sturdy fish: ><>> or <<>< Stretchy ...
16
votes
15answers
977 views

Generate MathJax for the Golden Ratio Continued Fraction

In anticipation of MathJax being temporarily disabled, the rendered MathJax in this question has been replaced with images. You are still welcome to post answers but you'll have to view the rendered ...
15
votes
32answers
3k views

Print the first character of the previous answers

I'd like to give credit to randomra, who helped me with my old idea and gave me this new one. Previous Winners Round 1: isaacg, with 7-bit ASCII Next bytes: 30 You know, code-golfing is really ...
26
votes
11answers
2k views

Official Ruby Inspector

Here is a simple ASCII art ruby: ___ /\_/\ /_/ \_\ \ \_/ / \/_\/ As a jeweler for the ASCII Gemstone Corporation, your job is inspect the newly acquired rubies and leave a note about any ...
6
votes
4answers
589 views

Write an URL compressor

Today your goal is to invent URL compression. You must write two programs: a compressor and a decompressor. The compressor will be called with one URL on stdin and its output will be read on stdout. ...
8
votes
4answers
227 views

Row, Column, Diagonal, Block

Write a square block of code that is N characters wide and N characters tall, for some positive integer N. For instance, your N may be 5 and the block look like this: ThisI sMy5B y5Cod eBloc kOkay ...
21
votes
3answers
857 views

How do I craft that?

There are 21 items in Minecraft that you can craft using only wood and items crafted from wood: axe boat bowl button chest crafting table door fence gate hoe ladder pickaxe ...
10
votes
4answers
368 views

Encoding an URL in brainfuck

Inspired by this question, your goal today is to encode an URL in brainfuck. My browser has been hacked! The location bar has been turned into a brainfuck interpreter. I need a program that turns an ...
11
votes
7answers
535 views

Generate a Brainf_ck program that outputs a string of given length

Your friend is trying to break into a vault that has a peculiar locking system: it requires a certain number of gentle knocks in a particular spot. Your friend discovered the number (which is in the ...
10
votes
3answers
265 views

Golfing every ASCII character in 99

99 is a programming language I invented earlier this week for my challenge Write an interpreter for 99. (Invented but never needed to implement thanks to half a dozen of you. ;) ) The full language ...
7
votes
6answers
629 views

Writing code for three tasks

When you run your program first, it should print an integer sequence. The second run should print the 'Mary had a little lamb' song. The third run should produce an ASCII image file. Scoring Your ...
9
votes
2answers
263 views

ICS Maritime Flag alphabet

The International Code of Signals flag alphabet is used by ships for communication, particularly for static signals. Your challenge is to write a program or function that will take a string from ...
9
votes
0answers
189 views

Golf a Particular Region of the Mandelbrot Set

The Wikipedia article on Kolmogrov complexity gives the excellent example that an image of a region of the Mandelbrot set takes millions of bits to represent as a bitmap, but would take far fewer bits ...
13
votes
1answer
391 views

Write a Kolmogorov Complexity Solver

The Kolmogorov complexity of a string S is the length of the shortest program P, written in some programming language L, whose output is exactly S. (Yes, the real definition is more formal but this ...
14
votes
9answers
1k views

Keep the unique characters down

It's very simple: Your program or function should generate the following text: Elizabeth obnoxiously quoted (just too rowdy for my peace): "THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG," giving me a ...
18
votes
21answers
5k views

The Staircase Challenge

Your work is to recreate this piece of art: _____ | | | | _____| ...
8
votes
6answers
307 views

List the Cases of Two Finnish Nouns

Introduction In this challenge, your task is to correctly list the cases of two Finnish nouns. The twist is that you may use one of the listings as a guide to produce the other. The Nouns We use ...
32
votes
8answers
4k views

One hundred passwords

I have one hundred vaults, each one within another. Each vault has a password, consisting of a single number. 95 43 81 89 56 89 57 67 7 45 34 34 78 88 14 40 81 23 26 78 46 8 ...
14
votes
3answers
785 views

Words within words within words within words . . .

In this pixelated font of uppercase letters of the alphabet, all the characters are 5 units wide and 5 tall. ███ ████ ███ ████ █████ █████ ████ █ █ █████ █ █ █ █ █ █ █ █ █ █ ...
10
votes
4answers
608 views

Put the line in the code you nut and shake it all up

Using one programming language write 5 single-line programs, each of which outputs a different line of the first verse to Harry Nilsson's 1972 song "Coconut" when run individually: Brother bought ...
3
votes
3answers
535 views

Generate all 4-perfect numbers

Your program or function should output all the 36 4-perfect numbers in increasing order separated by newlines. An n positive integer is a k-perfect number (multiply perfect number) if the sum of its ...
36
votes
14answers
4k views

Automate Saving the World

You are Desmond Hume. For the last 3 years, you and your partner, Kelvin, have been slave to a computer that requires a very specific sequence to be entered into it every 108 minutes to save the ...
29
votes
13answers
3k views

Morse the New Year

This is Weekly Challenge #1. Theme: Audio Processing Your task is to write a program, which writes an audio file to disc (in a format of your choice), which contains the Morse code for 2015, i.e. ...
12
votes
6answers
1k views

Output 2015 as QR code

Mission is simple. Just output number 2015 as QR code and write it to file named newyear.png in PNG format. Code must be valid any day, so maybe you shall not use current year. QR code as text looks ...
49
votes
9answers
4k views

Draw the Warm Welcome Secret Hat

Winter Bash 2014 is on its prime and don't we all love the hats ? Especially the secret hats! So why not draw one of secret hats ? The challenge Your task is to draw the Warm Welcome Hat in ...
60
votes
5answers
5k views

Recognise Stack Exchange Sites by Their Icon

After spending a while on Stack Exchange, I can recognise most sites in the Hot Network Questions by their little icon (which is also their favicon), but certainly not all of them. Let's write a ...
12
votes
6answers
625 views

12 Days of Golfmas

Challenge On each of the 12 days of Christmas, output the appropriate verse of "12 days of Christmas", according to the date, otherwise output the chorus of "I Wish It Could Be Christmas Everyday". ...
23
votes
13answers
2k views

DVI Connector Pins

This is supposed to be a code golf challenge on the simpler end of the spectrum. But I figured it could be nice to bring out some micro-optimisation here. There are three basic types of DVI ...
23
votes
13answers
2k views

It's Spanish Time!

I have a simple task that should be relatively easy to implement by means of code. Your goal is to write a program that will output the time written in Spanish, given the time in HH:MM format. Many ...
32
votes
8answers
2k views

How Many Guineas in a Gross of Threepennies?

Until decimalization in 1971, British money was based on dividing the pound into 240 pennies. A shilling was 12 pennies so 20 shillings made a pound. The smallest denomination was the farthing at one ...
-3
votes
5answers
683 views

The Most Complex Chinese Character

Challenge You must output the Chinese character for biáng. Your program must not access any external sources and must exactly reproduce this SVG in every way. Note that the image below is just a gif ...
11
votes
4answers
882 views

Convert x-illion into standard form

Given a string, consisting of a prefix and then "illion", convert this number into standard form. For example: "million" -> 10^6 "trillion" -> 10^12 "quattuordecillion" -> 10^45 The ...
47
votes
56answers
7k views

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 sentenced ...
-6
votes
1answer
214 views

Print Hamlet's monologue using as few characters as possible [duplicate]

The task here is to print the text below, using as few characters as possible in your code. You can't use any external resource. (file, stdin, network) To be, or not to be: that is the question: ...
41
votes
8answers
7k views

Draw the South Korean flag

When I stumbled upon this question I remembered that I had also once seen precise rules for the construction of the South Korean flag. And this is quite a different construction. Source: Wikipedia ...
18
votes
8answers
2k views

Pixel art, episode 2: Display the map 1-1 of Super Mario Bros

Last challenge (Pixel-art, episode 1: display Super Mario) was just a training... (and you completed it in amazing ways, thanks!) This time, you have to work a little bit more. You have to display ...
26
votes
20answers
5k views

Pixel-art, episode 1: display Super Mario

it's a-me! Today's task is simple: write a program, or a function that displays the idle small Mario sprite, from Super Mario Bros, on NES, over a blue background. Any kind of entry is valid as long ...
6
votes
2answers
406 views

Turn nouns into plurals

Your task is to take as input an English noun and output its plural. To win the challenge you must trade off code length against accuracy. Entries will be scored according to this comma-separated ...
17
votes
8answers
2k views

Print all Country Codes

ISO 3166-1 is the standard that defines all the country codes. The well-known two-letter codes (US, GB, JP, etc.) are called Alpha-2 codes. With two letters, there are only 262 = 676 possible codes, ...
63
votes
93answers
17k views

Sing Happy Birthday to your favourite programming language

Your favourite programming language has just had a birthday. Be nice and sing the Happy Birthday song to him (or her, if you will). Of course you should accomplish this by writing a program in that ...
7
votes
3answers
470 views

Anti-aliased ASCII Aureoles

Consider the following ASCII image of five concentric anti-aliased ASCII aureoles: ........ .@..............@. ..... ..... .@.. ...
12
votes
7answers
2k views

Print the Retro Rocket

(inspired by this SO question) You are given as input a single positive integer n. In as few characters as possible, output a rocket in ASCII art with a head, a tail, and a body composed of n ...
39
votes
13answers
5k views

Periodic Table of Elements - Code Golf

Based on Practical Golf - US States Your task is to find the abbreviation (symbol) of an element given the element name, up to and including ununoctium (118). Use the periodic table on Wikipedia. ...
22
votes
9answers
2k views

The Saltine Challenge

Here is an ASCII saltine cracker: _________________ | . . . | | . . | | . . . | | . . | | . . . | |_________________| Here are two crackers ...
7
votes
3answers
581 views

Help me with trigonometry!

Thank you guys so much for your help with calculus. Now I need some help with my upcoming trigonometry test. On the test, I'll need to simplify expressions. I’ll be given input like 4sin(x)/(2cos(x)) ...
14
votes
2answers
2k views

Draw ASCII Playing Cards

Consider these 15 ASCII playing card patterns (ace through Joker, and the back side), where X is a placeholder for the suit symbol: (they look better with less line spacing) ------------- ...
9
votes
5answers
839 views

Monkey Island: The Head of the Navigator

Warning: This challenge contains some mild spoilers for The Secret of Monkey Island. Towards the end of the game, you're being led through the catacombs by a magically preserved head of a navigator: ...
8
votes
3answers
520 views

Pigpen Cipher Encryption

Pigpen Cipher Encryption Your mission is simple: to write a program which receives text as input and outputs an ASCII representation of it in the Pigpen Cipher. Input ASCII-only (no Unicode) ...
14
votes
6answers
736 views

Electron Configurations

Electron Configurations Your mission is to accept an element's atomic number as input, and output its electron configuration (e.g. 2,8,8,2 for calcium). Input An atomic number from 1 to 118. You ...