Fuzzy Circles Edit I don't actually like this challenge all that much. Anyone who wants it can have it, else I'll get rid of it. Background For a real number x, let ⌊x⌋ be the greatest integer less than or equal to x. Challenge Given an input n, find the minimum radius of the circle such t...

Lucas and Fibonacci are in pair

Delimiter-Chaos Write a program of at most 150 bytes length that produces different outputs (to stdout) if you insert token-delimiters into the source code. Score The program with the highest number of different outputs wins. Rules For this challenge, we assume that the source code is token...

Largest and Smallest Numbers Printable code-challenge palindrone restricted-source Related: Largest Number Printable Your goal is to write code that produces a large number. However, when your code is reversed, you must output a small number. Rules No constants over 10 (like the other chal...

Write in Ge'ez! Ge'ez is a now-dead language used for liturgy in the Ethiopian Orthodox Church. It's traditionally written in a very distinctive script with many loops and curves. But for ease of reading, it's often transliterated into Latin letters. Your task here is to take some writing in Lati...

Pyramid of Bots king-of-the-hill In this game, your bot is trying to get as high off the ground as possible. However, it can only stand on top of other bots, which are trying to get higher, too! Overview Your bot should be a Javascript function. It's return value should tell the program if the bo...

Distinct Dice Sum Algorithm From a puzzle on Brainden. Paraphrasing, What is the best set of 8 sided dice, each identical, such that 3 dice can generate 120 distinct sums? "Best" means the minimum highest sided die configuration. With 7 sided dice, the best possible sides for each (...

Permutation Encoding Now posted to the main site. Check the revisions log if you want to see the WIP versions.

Compute strings with a fixed distance Consider a binary string of total length N. For example 000111000111 with \$N=12\$. We can store this string more efficiently by just recording the indices where bits are first flipped. In this case \$(3, 6, 9)\$ is sufficient information to reproduce the str...

King of the Grid There's a side-project of mine, simply titled My Grid Game, that's been sitting on lefttwix.com for a while. It was only a matter of time before it went automatic. The rules of the game are simple: Each player plays as a colour. Each player starts with a City (C) 2 spaces ...

Bijective base banana to decimal I'm trying to decide between 2 versions of this challenge: Prefixes version Let bijective base banana be bijective base 6 with each digit represented by a different prefix of the word "banana" as follows: 1: "b" 2: "ba" 3: "ban" 4: "bana" 5: "banan" 6: "bana...

Find the fixed point prime number-theoryfastest-algorithmrecursion Definition Let f(n) be the sum of the sums of each possible factor permutation of n. Determine (Y f)(n) (a fixed-point combinator) for all n from 2 to the input i (where i is an integer greater than 2). Example A quick example of...

Facto-RLE Task Given a non-empty string containing non-numeric printable ASCII characters, compute its facto-run-length encoded version. Definition Let \$S\$ be a non-empty string of length \$l\in\mathbb{N}^+\$ containing non-numeric printable ASCII characters. For each positive factor \$n|l\...

Compile Brainbash to BF code-golf Background BF is an esolang known for it's terseness and small character set. The language operates on a tape of unsigned 8-bit integers, and with a pointer to modify certain values. This pointer starts at the first cell. BF has the following commands availabl...

I recently made a language called bit, and your challenge is to create a valid program that takes 2 numbers from STDIN, and outputs the sum of them. You may assume the numbers are no more than 5 digits, and your output doesn't need to be more than 5 digits long Bit Specification You can find th...

The Input String, But Every Time It Says The First Word, It's Recursion You wanted to create the ultimate replacement remix, but didn't see a way to add more recursion that ends naturally. Then you saw The Entire Bee Movie But Every Bee Is Replaced With The Entire Bee Movie Without Bees. Unlike ...

Make it rotationally-symmetric code-golf (sandbox note: am I using the wrong terminology?) Background While looking at this challenge, I notice many some of the answers has 4-fold rotational symmetry. I think it would be convenient to have a program to automatically do it. Challenge Take i...

Nearest neighbors in a square lattice code-golf sequence square-lattice Premise Consider an infinite 2D square lattice. We can choose one point as the origin and label each point with a pair of integers that corresponds to points on the Euclidean plane: Now consider the point at the origin, \$(0...

king-of-the-hill I have an idea for a KOTH challenge (that is marginally similar to the current Reaper KOTH), but none of the expertise required to make it work. The idea is based on the card game Diamant aka Incan Gold, and the rules of the game are: The game is played over 5 expeditions, each...

My Ribosomes Got a Firmware Upgrade code-golf bioinformatics So all of the Apple iBosomes in my body have been updated to RibOS 4.0 now… while I appreciate the additional optimizations that were added, unfortunately for me they've dropped support for the legacy mRNA API. So since my RNA Poly...

Triangular snake You're given a triangular field: It has 4 ports. You're also given five different pieces from A to E: Each piece has a little piece of path inside it. Your basic goal is to build paths between ports. There are some rules: Each cell of the field can be occupied by 0 or...

Breaking into 3 Palindromes: As discussed here and here, every positive integer can be written as the sum of 3 palindrome integers. Given a number "n", output these integers. Challenge This is a code golf challenge. The shortest functional solution wins. The input number "n" will be any i...

Mini Castle Wars king-of-the-hill game javascript Note: This is very early draft, and I'll try to develop when I get some time to spare. Inspired by a previous KOTH based on a card game (but not actually a card game). Background This challenge involves a simplified version of the card game ...

Output the answer after yours code-golfstack-exchange-api Related: Output the answer above yours This challenge is very similar to the above, but I hope it's different enough to warrant posting. The difference is that you need to post the answer that is posted after yours (the whole answer, not j...

The Tiniest Generic Evolutionary AI code-golf ai test-battery Introduction The smallest program you can make (measured in bytes) that builds evolving AIs that parses unknown text string A into unknown text string B that still evolves. All languages are options. Internet connectivity is a...

Knight's tour code-golf chess A knight's tour is a sequence of moves of a knight on a chessboard such that the knight visits every square only once. For those who are not aware of how knights in chess work, knights are capable of moving in an L shape: Tours generally apply to a regular chessboa...

Write a program that takes a list of strings as input and creates trees of prefixes as such: Hi_there_how_are_you? Hi_there_would_you_mind? Hi_the_weather_is_nice Hills_are_green Many_of_us May_has_11_days May_has_11_days_left IWillLearnTheTrombone IWillLearnTheSaxophone IWillLearnThePiano Whi...

Put +, -, * into 1 _ 2 _ 3 ... n to make the expression equal 0, for a given 3 <= n <= 30, and output the valid equation (0=1+2-3). Exactly one operator between each number. There exists some patterns, such as ((1-2)-(3-4))+((5-6)-(7-8))... and 1+((2-3)-(4-5))+(6-7). Maybe we can find patterns...

code-golf I'm glad the sandbox exists because I have a few issues coming up with the right wording for this. Background Theoretically, any numeric pattern should exist somewhere in the decimal places of pi. Challenge Given any numeric input, find the index (location?) of the first occurrence...

Trilateration Intro: Similar to Trilaterate your position with a small twist. In a n x m array, Original Problem: You will be given a list of (x,y,d) as input, where d is the distance of your position from the point (x,y). Using this we can find our position. ................ In the above ...

There is a nice task One Ring to rule them all. One String to contain them all. But rule define a string as a linear buffer. A linear buffer is not a Ring :) My suggestion is: create a new task with title "One Ring to rule them all. One Ring to bring them all" add link to old task in the body ...

Making a Mountain out of a Molehill

Iterated Prisoner's Trilemma king-of-the-hill python Please send me problems or else I'm gonna post this on main. Prisoner's dilemma ... with three choices. Crazy, huh? Here's our payoff matrix. Player A on the left, B on the top A,B| C | N | D ---|---|---|--- C |3,3|4,1|0,5 N |1,4|2,2|3...

Prettify Pixiedust code-golf So Pixiedust is a new esolang I've created. One of the primary points is that it should look like pixie dust—exactly the things that your programs should fix. Input The input will be a program written in Pixiedust. Since this is not a challenge to parse the lang...

Iteration Hierarchy math code-golf function This is based on the m(n) map. mk takes in k functions and one natural input n, and iterates the first function n times onto the next argument, and then fills in the rest of the arguments. \$m_1=f_0\mapsto n\mapsto f_0^n(n)\$ \$m_2=f_1\mapsto f_0\ma...

Golf me a Bookmarklet Quine Given a javascript program (or any utf-8 text) of arbitrary length, output it in my simplified version of URI form, like a bookmarklet. You can use https://mrcoles.com/bookmarklet/ as reference. Output should be in the form javascript:[input with percent-encoding fo...

BF memory layout optimizer (posted). See the notes in the revision history. [please review other sandbox posts]

It seems \$2^n\$? Let \$a_0=1\$ and \$a_{i+1}=1+\sum_{j=0}^ia_i\$, then \$a_i=2^i\$, which is no fun. Now we reverse half of the value, \$a_{i+1}=L(1+\sum_{j=0}^ia_i)\$ for odd \$i\$, where \$L\$ reverse the number, e.g. 15=>51, 1230=>321. Solve \$a_i\$. You can choose 1-index, or reverse each ou...

Concatenated halting problem: no + no + ... = yes code-challenge source-layout halting-problem Challenge Write \$n \ge 2\$ distinct programs \$P_1, P_2, \cdots, P_n\$ in a language \$L\$ of your choice, which satisfy the following property: \$P_1 P_2 \cdots P_n\$ (where \$XY\$ means string conca...

Prime Factorization code-golf math number-theory factoring primes Although there was a prime factors challenge posted ten years ago, it has tedious I/O and restricted time. In this challenge, your task is to write a program or function which takes an integer \$n \ge 2\$ as input, and returns its...

Backromymiser code-golf string subsequence Background A backronym is an acronym that was formed from an existing word. For example, spam is actually named after the canned meat product as used in the Monty Python sketch, but can be interpreted as "stupid pointless annoying mail". They can also b...

Assume a standardized test has \$15\$ multiple choice questions, with \$3\$ options each. A school has some students and wishes for at least one of the students to get \$10\$ correct answers. Since no one in the school knows any math they are going to cheat and tell each student which answers he ...

Yes. Me again. However, I have an idea for a king-of-the-hill challenge. It is... KotH - Create a a program-fighting program! Background You are a programmer who has been requested to create a self replicating program that wipes out other self-rep programs. However, you need to have your self-rep...

Solve the halting problem for S combinatory logic code-golf functional-programming lambda-calculus halting-problem decision-problem Background Combinatory logic is a system where a term is written using a finite set of combinators and function application between terms, and reduction rules are de...

Prime Factorization - but on the exponents too Though there is a prime factorization challenge and it's here, this, I feel, will be a bit more interesting than that one. To understand this, let's have an example; I will use 5,184 for this. \$5184 = 2^6 * 3^4\$. However, for this challenge, such a...

Given an integer \$ n \ge 2 \$, you need to calculate \$ \lfloor n \log_2(n) \rfloor \$, assuming all integers in your language are unbounded. However, you may not ignore floating-point errors - for example, in python lambda n:int(n*math.log2(n)) is an invalid solution, because for example for n=...

Related: Multiply Quaternions Challenge Given a string made of ijk, interpret it as the product of imaginary units of quaternion and simplify it into one of the eight possible values 1, -1, i, -i, j, -j, k, -k. The evaluation rules are as follows: $$ ii = jj = kk = -1 \\ ij = k, \quad jk = i, \qu...

Background Gödel numbers are a way of encoding any string with a unique positive integer, using prime factorisations: First, each symbol in the alphabet is assigned a predetermined integer code. Then, to encode a string \$ x_1 x_2 x_3 \ldots x_n \$, where each \$ x_i \$ represents an symbol's int...

I'm currently working on a challenge which involves writing JavaScript players for a board game. I've also recently discovered private fields in JavaScript (a recent addition), which I thought would be useful to prevent entries from accessing forbidden objects and cheating the game. The only trou...