Questions tagged [compression]
Related to compressing or decompressing arbitrary data. Challenges which relate to compressing a single specific input should instead be tagged [kolmogorov-complexity]
94
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I want 8 bits for every character!
This is the reverse of this challenge.
Given an encoded list of codepoints and the characters used to encode it, you need to decompress it to its original string.
For example, given the encoded list <...
- 4,216
8
votes
6
answers
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Random Pixels Image Compression
Challenge:
Given an integer \$n\$, guaranteed to be \$\geq2\$ and a power of 2, we are going to draw multiply boards either side-by-side or below one another, where the first has dimensions of \$n\$ ...
- 103k
21
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Who needs 8 bits for one character?
Given a string and the characters used to encode it, you need to compress the string by only using as many bits as each character needs. You will return the character codes for each character needed ...
- 4,216
-2
votes
1
answer
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Program compressor
Choose a language and write a program in the language that:
Take a valid program of the language as input,
Output a string(bytearray, etc.). It needn't be a valid program.
Only finite valid inputs ...
- 12.7k
13
votes
8
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561
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Compress and decompress
Your task is to make a bidirectional compressor. It takes a list of bytes as input and returns a list of bytes as output. It has the property than whenever it is iterated twice it returns the original ...
- 6,655
10
votes
2
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Smallest possible Scratch 3.0 project file (SB3)
The objective is to make the smallest SB3 file that can simply be imported into Scratch 3.0 without a "The project file that was selected failed to load" error. Any means can be used, like ...
- 199
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0
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Jelly compression quine
The golfing language Jelly has a very complex and clever string compression system which I'm not going to go into depth about here. You can find a very good explanation here.
Basically, Jelly's string ...
- 27.6k
14
votes
2
answers
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What's my TIO uniqueness?
Try it online! currently has 680 listed languages, all of which are searchable. For most of those languages, when searching for it, you don't have to enter the entire string. For example, entering <...
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7
answers
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Reverse Zip Bomb
A zip bomb is a compressed file, designed so that unpacking it yields the biggest file possible. These are fairly well known, and there are examples of 42 KB files which expand into multiple petabytes ...
- 17.1k
19
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3
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Decompress an integer, Jelly style
Jelly has compressed string literals, using the “...» delimiters. The way these work is by interpreting the ... as a base-250 ...
12
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9
answers
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Naïve compression
using Prefixed Length Code
We are going to implement a compression of text (string, array/list of characters/bytes) by simple substitution of each character by a binary code, based on the frequency of ...
- 20.5k
10
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Breaking Bad - ize any string (compression) [duplicate]
The TV series "Breaking Bad" replaced the letters Br and Ba with a periodic-table like representation, printing [Br35]eaking [Ba56]d.
Create a program ...
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Golf a golf chart
Given a distance in meters as an integer \$60\le d \le 260\$, return the number of clubs that may be used according to the following arbitrary chart, where both \$min\$ and \$max\$ are inclusive:
<...
- 166k
25
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14
answers
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11
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Cheat activated
Background
The game Grand Theft Auto: San Andreas went down in history also thanks to its wide selection of cheats. They're almost 90 and anyone who has ever touched this game, no doubt has tried ...
- 1,973
37
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lc's dvntrs n Wndrlnd
The task
Today's special offer: consonants and punctuation for FREE!
Your program or function will be given as input the first 6 paragraphs of Lewis Carroll's famous novel Alice's Adventures in ...
- 166k
18
votes
34
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Compactify the input
Given a word, your task is to compact it by saving its first character and removing any other vowel (aeiou).
Input
Your input can be the word in STDIN, a function argument or any other input format ...
- 3,073
19
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14
answers
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Let's decompress a bit
Given a compressed string \$s\$ made of printable ASCII characters (32 to 126), your task is to print or return the original text by applying this simple decompression algorithm:
Start with \$k=0\$
...
- 166k
2
votes
0
answers
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Predictor Generator [closed]
Write a program that when given a string \$S\$, it generates a program of the same language as itself.
The generated program, when given a continuous substring of \$S\$, should predict the next ...
- 659
9
votes
1
answer
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Caddyshack or: How to compress already-golfed code
In golf, a knowledgable caddie helps an already good golfer to be even better. In this challenge, you build a "caddie" to help you code golf. In particular, your caddie will compress golfed code in ...
- 2,229
28
votes
16
answers
7k
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.-...--..---.-...--..... the red-nosed reindeer
Can you recover a sequence of letters from a sequence of dots and dashes? In Morse code, x is represented by -..-, but without ...
- 2,229
3
votes
4
answers
482
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Compress my Malbolge!
Background
Malbolge is truly intriguing language. But programs written in it are also extraordinairly huge (and in some cases, unpostable on PPCG).
Your challenge (shall you accept it) is, to ...
- 11.3k
14
votes
2
answers
963
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Create the least compressible picture
"A picture is worth a thousand words"—so the old saying goes. The average word is about four characters long, so a picture conveys 4kB of information. But how much entropy, rather than information, ...
- 1,447
9
votes
2
answers
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ASCII Maze Compression
Challenge
Design a compression algorithm specialized for compressing ASCII mazes. You will need to create both a compression algorithm and a decompression algorithm. Your score will be based on the ...
- 9,791
2
votes
7
answers
372
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Countries by Area
Challenge
Given two non negative integers a < b, output all countries, from the below Top 100 Countries, where area is between ...
- 2,793
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4
answers
1k
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Generate Matlab plot markers
Matlab has a useful command for visualizing data: plot. It draws data points using "markers" in 2-D space, connecting them with lines; however, for this challenge, ...
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1
vote
4
answers
455
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Send the pairs in smallest output
Write two programs A and B.
Program A (the encoder) takes 1024 pairs of integers \$(k,v)\$, where \$0≤k<2^{32}\$ and \$0≤v<1024\$, and all \$k\$ will be different. It will output a single ...
- 12.7k
9
votes
33
answers
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Output some reserved words
For a computer language, a reserved word is a word that cannot be used as an identifier, such as the name of a variable, function, or label. For other computer languages, keywords can be considered as ...
- 2,793
8
votes
3
answers
543
views
Compress to Impress
Inspired by both the challenge "Unique is Cheap" by @Laikoni, where the score is based on the challenge itself, as well as the JavaScript (ES6) answer of @ETHproductions for the "...
- 103k
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votes
10
answers
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Compressing the Atomic Ionization Energies
This is a different type of compression challenge. In a normal kolmogorov-complexity challenge, you are required to recreate a list exactly. Here, you are allowed to round the values in any way you ...
- 28.5k
36
votes
18
answers
3k
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Bracket Expansion!
Your challenge is to expand some brackets in a program's input as shown:
Find a string s between two matching brackets [ and ], ...
- 13.2k
15
votes
4
answers
898
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Palindrome Compression
Challenge
Write a program that compresses and decompresses ASCII text losslessly. It should be specialized to work well with palindromes, including case-insensitive and punctuation-insensitive ...
- 9,791
317
votes
23
answers
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Write Moby Dick, approximately
Here is a 1.2Mb ASCII text file containing the text of Herman Melville's Moby-Dick; or, The Whale. Your task is to write a program or function (or class, etc. -- see below) which will be given this ...
- 7,102
27
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8
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Somewhere On The Tube ...But On Which Lines?
The London Underground A.K.A. The Tube is the oldest underground railway in the world, it currently consists of eleven lines* servicing 267 named stations (strictly 269** stations since "Edgware ...
- 91k
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votes
12
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Simple State Sales Tax Calculator
Sales taxes in the United States are complicated, to say the least. Generally, there's a state sales tax (there are a handful of states that do not collect a state sales tax), but there could also be ...
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20
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All your base 97 are belong to us
Many programming languages are written using solely printable ASCII, tabs and newlines. These 97 characters are then stored in 8-bit bytes (which are actually capable of holding 256 different ...
- 9,336
9
votes
2
answers
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Smallest chess game compression
Inspiration:
Heavily inspired by Smallest chess board compression I decided to make a similar but distinctly different competition.
tl;dr
Take the file Chess_Games.txt and compress it as much as ...
- 235
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votes
6
answers
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Compressing RLE data to draw ASCII art
This question is based on what I came up with to answer another question.
Sometimes the questions here ask to draw some ASCII art. One simple way to store the data for the art is RLE (run-length ...
- 12.6k
-6
votes
2
answers
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Output the Wikipedia article for Kolmogorov Complexity
Your job is to output the html of the current version (at the time of this writing) of the Wikipedia page for Kolmogorov complexity: https://en.wikipedia.org/w/index.php?title=Kolmogorov_complexity&...
- 7,069
30
votes
11
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Which wire to cut
This task is about compressing and processing a sequence of conditionals.
In the game Keep Talking and Nobody Explodes, a bomb defuser must disarm a bomb with the help of instructions relayed by ...
- 137k
11
votes
13
answers
1k
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The weird and wild bean game
Maybe some of you already know this game: you have a collection of jelly beans of different colors. For every color, the bean can have different tastes, some are good and some are bad, and you cannot ...
- 12.6k
25
votes
1
answer
813
views
Maximal discrepancy-2 sequence with minimal entropy
Background
As noted in the PPCG challenge Compress a maximal discrepancy-2 sequence – which inspired this challenge – the authors of the paper Computer-Aided Proof of Erdős Discrepancy Properties ...
- 206k
29
votes
24
answers
3k
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Converting "0xUsernames"
0xUsernames
There's so many people using a messaging service that they're running out of space to store all the usernames! To fix this, they are going to start storing usernames as hexadecimal, where ...
- 13.9k
35
votes
10
answers
3k
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Help me recognise my monster
Background
The computer game NetHack dates from 1987, before the use of graphics in computer games was widely established. There are lots of monsters in the game, and potentially a lot need to fit on ...
user62131
9
votes
1
answer
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The Most Durable Pokemon Types
Background
This question is similar to this one. I have provided all of the information needed below. If you are familiar with the other challenge then note that we are ranking all defenses instead ...
- 93
1
vote
0
answers
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Self compressing/decompressing program [closed]
Challenge:
Write a lossless encoder/decoder that is able to compress its own source code.
Usage:
progname encode
Encodes ...
- 307
8
votes
10
answers
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DNA Encode a String
Challenge
You must write an encoder (and a separate decoder) which takes a string as input and outputs the string encoded in the style of a strand of DNA.
DNA
DNA is made up of four types of ...
- 22.8k
2
votes
0
answers
481
views
100KB image compression [closed]
Your task is to, given an image, compress it to 100000 bytes or less, while following all of the below rules:
No cheating/loopholes.
Your code must not be optimized to work best only on the test set ...
20
votes
1
answer
502
views
Diff compression [closed]
For this challenge, you need to compress a diff. A diff is some data that represents the difference between two strings. For this challenge, you need to provide one or more programs that can:
Input ...
- 14.2k
18
votes
2
answers
870
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Thwart Lepton compression
Dropbox recently released Lepton (GitHub), a method that losslessly compresses JPEG images round-trip, saving an average of 22%.
Because of the pigeonhole principle, any general compression algorithm ...
- 3,267