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 existing challenges.

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Kolmogorov complexity Chad Gadya [duplicate]

EDIT It is not clear how answers to the question of compressing a long text, without cumulative properties are relevant to golfing a short cumulative strong, any more than general Lempel Ziv ...
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8answers
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Build a triangle without any triangles

As a little kid, I liked to play with these toys a lot: They probably intended for these to be used for art, but I always used them for math! Fractals, patterns, etc. One time, I was given this ...
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420 <s>Blaze</s> Golf It

This is a pretty simple challenge, but (I hope) a fun one. Task If right now either the month is 4 and the day is 20, the hour (on a 12 hour clock) is 4 and the minute is 20, or the minute is 4 and ...
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4answers
310 views

Code a code page

Introduction A code page maps integer values to a specific character. We can visualize a code page like this: +---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+ | | 0 | 1 | 2 | ...
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Display “Happy Easter!”

Your task is to print the following: _ _ _______ _ | | | | (_______) _ | | | |__ | | ____ ...
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2answers
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Fun with flags!

Write a full program with a source code of 256 bytes or less that looks at an image of a flag and determines what country that flag is from. A zip file containing the 196 different flags in the ...
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16answers
362 views

Draw an ASCII art phone keypad

Draw the following in the fewest bytes possible: ------------------------- | | ABC | DEF | | 1 | 2 | 3 | ------------------------- | GHI | JKL | MNO | | 4 | 5 | ...
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1answer
255 views

Golf English – using contractions

I have not laughed as much from Stack Exchange content as I have from this. I think you all will enjoy this challenge, as it is inspired by what is over there. You will write a function or program ...
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2answers
121 views

Generate E-series of preferred numbers

Resistors and other electronic components are typically manufactured with values that conform to one of the E-series of preferred numbers. IEC 60063 defines the following E-series: E6: 10 15 ...
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How many sides does this polygon have?

So in 1st grade math, you learn the names of polygons. Three sides is a triangle, 4 is a square, and 5 is a pentagon. However, in 1st grade honors, you go a bit further. Your challenge There is a ...
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5answers
388 views

Electoral votes from state name

Given a the name of a state of the United States as a string (with case), return the number of votes the state has in the Electoral College. Write a full program or function, and take input and output ...
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Is this number random?

I asked random.org for 128 random integers between 0 and 232 - 1. Since the random number generator was so eager to give the first 64 numbers first, they're obviously more random than the other 64. ...
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15answers
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Code Golf Golf Score

It's Friday... so let's go golfing! Write code that determines the player's scoring on a hole in a game of golf. The code can be either a function or entire program. As the genre suggests, shortest ...
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How many characters are there on the icon of a Stack Exchange site?

Given the name of a Stack Exchange site which doesn't have their own design yet, decide how many ASCII characters (non-ASCII ones are counted separately) are there on their icons. Your code should ...
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Draw an ASCII house

This is a window: --- | | --- Let's add some walls |. Put two spaces on either side of it so that the window has plenty of room. | --- | | | | | | --- | Now let's add a roof and a ceiling. ...
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7answers
692 views

Surrounding Countries

Ever wonder what countries surround another? I do too, sometimes, and, well, here's the challenge for it. I have provided a list of countries and the countries that they touch that you must recognize ...
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10answers
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Quack the Angry Duck

No one is quite certain what the emoticon >:U is intended to represent, but many scholars believe it looks like an angry duck. Let's assume that's the case. Task Given an integer n between 0 and ...
6
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1answer
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It's the end, but the code-golf has been prepared for

Welcome to BBC Casting. We need a program that we can use to select a new actor to play The Doctor on Doctor Who. In the spirit of the show, your program will perform a regeneration from one actor's ...
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Picture of an old friend in ASCII art

I hope this picture looks familiar to you. It's one of Pacman's ghosts in his "vulnerable" state, after Pacman has eaten a power pill. The challenge Picture our ghost in a little frame, using ...
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3answers
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LaTeX Table Generator

Write a function or program which, given a number of lines and columns, generates a corresponding tabular environment for LaTeX with no data in it. Table format and tabular Environment Here is an ...
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Put on your sunglasses

Introduction You are probably familiar with the "puts on sunglasses" emoticon-meme: (•_•) ( •_•)>⌐■-■ (⌐■_■) In this challenge, your task is to take the first line as input, and output the last ...
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1answer
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Output the given English pronoun table

Output the provided table of English pronouns exactly, in as few bytes as possible. Code rules The code will take no input The table is tab-delimited Each line begins with a single tab \t if there ...
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2answers
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Convert to ASCII Agrippa Numbers

Challenge Given a natural number, output it in the ASCII form of Agrippa's number system. Description I like odd alphabets and numeral systems. My favorite numeral system is one given by Heinrich ...
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Output all the white or black squares of a chessboard

Introduction This is how a chessboard looks like. You can see that a1 is a dark square. However, b1 is a light square. The Task The challenge is, given dark, light or both, output all the ...
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Output the current time in ascii art

Challenge Your task is to output the time (in 12 hour time) in ascii art. All characters that will be used are as follows: ___ __ ___ ____ _ _ _____ __ ______ / _ \ /_ | ...
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3answers
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How many words of power did I shout?

In Skyrim, the player character can use powerful magic shouts (Thu'ums) to achieve their goals. Every shout consists of three words, however, the player can use the first one or two words to achieve ...
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Convert English to a number without built-ins or libraries

This challenge is similar to this other, however I made a restriction (see bold text below) that I think would made it much diffent and (I hope) fun either. The Challenge Write a program or a ...
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Print cos(2π/17) exactly

One way to construct a regular heptadecagon starts with drawing a horizontal line of length 1 from the center to a vertex. Then the distance along that line from the center to the second vertex is ...
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Go generate some Java

Your boss wants you to write code like this: public static boolean isPowerOfTen(long input) { return input == 1L || input == 10L || input == 100L || input == 1000L || input == 10000L ...
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48answers
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Generate 100 Java Tuple classes

Write a script that writes to standard output, or your language's equivalent, 100 lines of (valid) Java code that begins with: class Tuple1 {public Object _0;} class Tuple2 {public Object _0,_1;} ...
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Output all valid classful public unicast IPv4 addresses

IPv4 addresses are 32 bits wide, and thus the size of the address space is 232, or 4,294,967,296. However, this is only a theoretical upper-bound. It is not an accurate representation of all the ...
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4answers
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Strategies for representing a given large integer using arithmetic expression

I have a specific number in mind, but it's part of a challenge I'm doing, and I don't want people to do (all) the work for me. Here is a number which has the same digits, but shuffled: ...
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12answers
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Eeny, meeny, miny, moe

Introduction The childhood song Eeny, meeny, miny, moe was often used to select who was "it" when playing tag. Everyone would stand in a circle and point at one person selected at random. They ...
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Encode bytes to PGP wordlist format

The PGP Word List is a set of 512 English words for verbally communicating strings of bytes, such as authentication codes or hashes. It is used in secure VoIP software as well as in some other ...
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Build an English word syllable counter

Write a program or function to estimate as closely as possible the number of syllables in English words. The input list is here: 1000 basic English words. There are only 997 words because a few ...
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13answers
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Create an ASCII-to-hex table for Mark Watney

Inspired by this SciFi.SE question. Background (with minor spoiler): Challenge With no input, output the following ASCII table exactly like this: Dec Hex Dec Hex Dec Hex Dec Hex Dec ...
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15answers
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Chinese Zodiac of the year

2015 was the year of the goat! In this challenge, you will figure out which animal represents the year. To avoid making this challenge to complex you won't need to calculate Chinese new year. Because ...
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6answers
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Using Symbols for Letters

Input: A single word as a string (matches [a-zA-Z]+). If the input doesn't follow these guidelines, print "Error" (but no error should be thrown) Output: The NATO pronunciation of the word. Print ...
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What song is playing?

Inspired by this xkcd You work for Shazam and they have a project for you. Some customers are complaining about their app taking up too much space on their phone, so they want you to code a lite ...
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Merry Christmas (and a Happy New Year) [duplicate]

The goal of this challenge is to create a program that outputs a string depending on the time of year. Output If the date is December 25, output: Merry Christmas! If the date is December 31 or ...
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12answers
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Help Trump build the wall!

Trump needs the wall constructed and you are going to do it! To most efficiently build his wall I have created a simple, repeatable pattern for you to use: __ __ | |_| | ___| ...
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2answers
321 views

Forgotten Realms date calculator

In an effort to level the playing field between languages with built-in date libraries and those without, let's work with a fictional calendar. The Forgotten Realms are a (the?) campaign setting for ...
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16answers
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A multiplication table for the Cheela

The Cheela (from the book Dragon's Egg by Robert L. Forward) are creatures that live on the surface of a neutron star. Their body is flat and circular with twelve eyes on the perimeter, so they ...
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Unfolding the Hexagony source code

Introduction If you're not familiar with Hexagony, it's an esoteric language created by Martin Büttner. The thing is that this language accepts multiple forms for the program. The following programs ...
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5answers
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8-bit Chess Pixel Counting

Goal You're playing a computerised chess game. The display is in black and white only and the pixels are chunky. White pixels use a lot power compared to black pixels and you're concerned about ...
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8answers
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The alphanumeric spiral

The task is very simple, when given an input, output one of the following spirals: Input = 1 gives a spiral with the letter A beginning in the top left corner: A B C D E F T U V W X G S 5 6 7 Y H R ...
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9answers
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Basic Latin character name to character

Let's get back to basics! Your code, a complete program or function, must convert the official Unicode name of a printable Basic Latin character into the corresponding character. For example, for ...
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5answers
310 views

Can't see the forest for the keys

Write a program or function that takes in a nonempty list of integers in any reasonable convenient format such as 4, 0, -1, -6, 2 or [4 0 -1 -6 2]. Print or return a string that depicts the list as ...
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5answers
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Find that zipcode!

Italian zipcodes are 5-digit numbers. Each number is linked to a province. There are 4610 zipcodes and 110 provinces (as of 2015) in Italy. Given the list of zipcodes and the related province (in ...
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Guess my password! (Code Golf) [duplicate]

So, like the title says, today you are going to guess my password (sort of). You need to make a big long list of every possible password I might be using on my 4 digit online vault. Specifications: ...