Questions tagged [encoding]
This challenge relates to data expressed under a different representation or language (including encoding, decoding, and processing such data). Some examples of an encoding includes ASCII and UTF-8.
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Encrypting Emojis
Problem
You are tasked with creating a program that performs emoji encryption on a given string of emojis. In this encryption scheme, each emoji is replaced by a unique character (from ...
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Representing a number as an unordered list of smaller numbers
Suppose we want to encode a large integer \$x\$ as a list of words in such a way that the decoder can recover \$x\$ regardless of the order in which the words are received. Using lists of length \$k\$ ...
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Gödel encoding - Part II (decoding)
Part I
Previous part was considered encoding of non-empty nested lists with a positive integer.
Reminding the coding procedure \$G(x)\$:
If \$x\$ is a number, \$G(x) = 2^x\$
If \$x\$ is a list \$[n_0,...
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Gödel encoding - Part I
Related but different.
Part II
Taken from the book: Marvin Minsky 1967 – Computation:
Finite and Infinite Machines, chapter 14.
Background
As the Gödel proved, it is possible to encode with a unique ...
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Decoding a non injective bit matrix encoding
The problem
Someone has created an encoding format for square bit matrices, however they have found it isn't perfect! One encoding may not decode to exactly one matrix, or it may not even be possible ...
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Storing the code in unary [closed]
Your goal is to create a program that can store another program … in unary. The main program uses the unary to run the program encoded in it, as if you were just running the encoded program normally. ...
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Output the length of (the length plus a message) [duplicate]
The task is simple. You're given an arbitrary string message. Return that message prefixed with a number, such that the length of that number plus the message equals the number. In other words, the ...
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Encoder/Decoder for efficient number storage!
Description
Inspired by this question, write a program/function to encode a number and a program (possibly the same as the first) to decode a bitstream in variable-length encoding as follows (taken ...
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ro1000an nu1000era50 en100o501ng
In the hovertext of this xkcd:
There's an "encoding" based on replacing runs of roman numerals with their sums. To do this:
Find all runs of at least 1 roman numeral (...
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Nega-Zeckendorf representation
Background
Zeckendorf representation is a numeral system where each digit has the value of Fibonacci numbers (1, 2, 3, 5, 8, 13, ...) and no two consecutive digits can be 1.
Nega-Zeckendorf ...
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Encode a Lenguage
The Len(language,encoding) family of languages is a variety of Lenguage derivatives. To encode a program into a Len language, you replace every character with its representation in a certain encoding, ...
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Encode USB packets (part 2)
Inspired by this video by Ben Eater. This challenge forms a pair with Decode USB packets.
The USB 2.0 protocol uses, at a low level, a line code called non-return-to-zero encoding (specifically, a ...
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Decode USB packets
Inspired by this video by Ben Eater. This challenge forms a pair with Encode USB packets.
The USB 2.0 protocol uses, at a low level, a line code called non-return-to-zero encoding (specifically, a ...
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Build a program that outputs itself encoded as a QR [closed]
The goal is simple. Write a program that outputs itself encoded as a QR code.
A QR code is a way to encode data in a black and white image, similar to a 2D image.
An example implementation can be ...
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Implement swap encoding
Swap encoding is an encoding method where you iterate through a string, reversing sections of it between pairs of identical characters.
The basic algorithm
For each character in the string:
Check: ...
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Decode Polybus Square/Tap Code/Prison Code
The code has a lot of names, but is very simple:
1 2 3 4 5
1 A B C D E
2 F G H I J
3 L M N O P
4 Q R S T U
5 V W X Y Z
A letter is coded by its coordinates, ...
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Elias omega coding: decoding
Related: Elias omega coding: encoding
Background
Elias omega coding is a universal code which can encode positive integers of any size into a stream of bits.
Given a stream of bits \$S\$, the decoding ...
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Elias omega coding: encoding
Background
Elias omega coding is a universal code which can encode positive integers of any size into a stream of bits.
Given a positive integer \$N\$, the encoding algorithm is as follows:
Start ...
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12
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Store eight bits on a punched card
A little while back, data was frequently stored on punched card. A typical card would have 80 columns of 12 possible 'punch' positions. A plethora of encodings was used, each for their own specific ...
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Japanese Encoding Conversion
Background
In JIS X 0208 a 94 by 94 map (kuten (区点)) is defined to encode Chinese characters (kanji), phonetic moras (kana) and other symbols. Along with this standard there are 3 different encodings ...
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Find all possible dates [closed]
You get a string which contains an integer between 1000 and 99999999 as input. The input string might contain leading zeroes but ...
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Decode an URL string
Challenge
I think everyone of us heard of URL encoding mechanism - it's basically everywhere.
Given an URLEncoded string on stdin, decode it, and output the decoded form to stdout.
The encoding is ...
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Mis-decode a date
Background
Inspired by a now deleted question by John Burger from which I quote:
Now obviously no human made this mistake. It's a mis-decode of something - perhaps the ISBN? My question is: ...
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Clock (transliterate) Cipher
Introduction:
I have loads of different ciphers stored in a document I once compiled as a kid, I picked a few of the ones I thought were best suitable for challenges (not too trivial, and not too ...
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Trifid Cipher (without keyword)
Introduction:
I have loads of different ciphers stored in a document I once compiled as a kid, I picked a few of the ones I thought were best suitable for challenges (not too trivial, and not too hard)...
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Computer Cipher
Introduction:
I have loads of different ciphers stored in a document I once compiled as a kid, I picked a few of the ones I thought were best suitable for challenges (not too trivial, and not too hard)...
- 123k
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19
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Decode a 7-segment display
You probably all know the 7-segment display which can display among other things all digits from \$0\dots 9\$:
Challenge
We only consider the segments \$\texttt{A}\dots\texttt{G}\$, your task is to ...
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Encode - Shuffle - Decode
Challenge
Your task is to encode an integer as a string of ASCII characters, then successfully decode it after said string has been randomly shuffled.
You will write two programs/functions, which ...
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Permutation Encoding
Write a program which can encode text to avoid reusing characters, and convert back.
Both normal and encoded forms are restricted to a particular character set: the space character ...
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Bijection: tree-like lists - natural numbers [duplicate]
We define a tree-like list, or trist for short, as the empty list or a list containing only previously constructed trists.
The natural numbers can either include 0 or not, according to your ...
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Bake me some moji
Given a string, character list, byte stream, sequence… which is both valid UTF-8 and valid Windows-1252 (most languages will probably want to take a normal UTF-8 string), convert it from (that is, ...
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Professor at MIT can read minds!
The task is taken from an MIT lecture by Prof. Devadas called You can read minds. A detailed explanation of the trick can be found in the linked video, or in this document. I'll try to explain it in ...
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Prime Factor Encoding
How the encoding works
Given a list of bits:
Hold a prime (starting with 2)
Have a list
For each bit in the input
If it's the same as the previous bit, add the ...
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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 "...
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Balanced Zero-One Encoding
Task
Encode a string that entirely consists of uppercase alphabets (A-Z) using only zeros and ones, using your own favorite scheme. But the rule isn't that simple!
...
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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 ], ...
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1
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Decode my I2C Stream!
From the sandbox!
I2c or TWI, is a 2 way stream that uses 2 signal lines: SDA and SCK. This is used in sensors to communicate ...
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1
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Braincopterify an image
Introduction
Braincopter is an esoteric Brainf*** derivative that encodes a Brainf***
program as an image. As a 2D language, it uses two additional commands; they
rotate the instruction pointer (...
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Telegraphy Golf: Decode Baudot Code
Background
In 1870 Émile Baudot invented Baudot Code, a fixed-length character
encoding for telegraphy. He designed the code to be entered from a
manual keyboard with just five keys; two operated with ...
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Double run-length encoding
Everyone knows what run-length encoding is. It has been the subject of many code-golf challenges already. We'll be looking at a certain variation.
Example
...
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Implement an encoder for RFC 1924 IPv6 Addresses
Introduction
Everyone should know IPv6 by now. IPv6 has very long, cumbersome addresses.
In 1996 some very intelligent people created a scheme to encode them much better in RFC 1924. For reasons I ...
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Code the Huffman!
Or else he will huff and puff and blow your house down!
That was completely irrelevant. This challenge is actually about Huffman coding. The gist of it is the frequency of characters in a given text ...
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Have you learned your fib-abc?
I don't like numbers, but I do like the Fibonacci sequence. I'm sure we could work something out.
Please read one integer n from STDIN and output the nth Fibonacci number in base 26 (...
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Dynamic Encoding: A CIA Mission [closed]
The Challenge Mission
You are Jim, a CIA agent in charge of super secret spies around the world. However, your enemies, the Naissurs, are highly trained in computer intelligence, and they can hack ...
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Implement bzip2's run-length encoding
Background
After applying the BWT (as seen in Burrows, Wheeler and Back) and the MTF (as seen in Move to the printable ASCII front), the bzip2 compressor applies a rather unique form of run-length ...
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Move to the printable ASCII front
Background
The move-to-front transform (MTF) is a data encoding algorithm designed to improve the performance of entropy encoding techniques.
In the bzip2 compression algorithm, it is applied after ...
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Confuse the Dakotas [closed]
You have been hired by the government of North Dakota to encrypt the state's communications. Write two programs, one to encrypt a message and one to decrypt that message.
The government is not really ...
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Underground geek rock band names
We have a group of stealthy computer-savvy geeks who are also musicians with a very subversive element to their songs that the authorities in their totalitarian country just can't stand, and are ...
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Encode a string for aliens that read and write English, but don't know ASCII
Turns out there are some distant aliens who know English (and have coincidentally standardized on 8-bit computer architectures). Yet they have never heard of ASCII, nor even alphabetical order.
It ...
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Convert a bytes array to base64
Your mission is to write a function/program that converts an array of bytes (i.e: an array of integers from 0 to 255), to base64.
Using built-in base64 encoders is not allowed.
The required base64 ...
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