# Questions tagged [code-golf]

Code-golf is a competition to solve a particular problem in the fewest bytes of source code. If you want to score by characters instead of bytes, please state this explicitly in the challenge. If source code length is not the primary scoring criterion, consider using another tag instead.

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### Havel-to-da-Hakimi [duplicate]

It was a dark and stormy night. Detective Havel and Detective Hakimi arrived at the scene of the crime. Other than the detectives, there were 10 people present. They asked the first person, "out of ...
14k views

### Dad jokes are fun

We all know the classic dad joke that goes something like this: Somebody says a sentence to describe their self (e.g. I'm tired or ...
5k views

### Gravitational Force Between Numbers

The gravitational force is a force that attracts any two objects with mass. In this challenge our objects will be Numbers and their mass will be their value. To do so, we don't care about the strength ...
202 views

### Sliding retrieval

Thanks, Uncle (the story) My slightly mad uncle recently left for the space colonies, and passed his pallet goods business to me. The rectangular warehouse is full of pallets of goods except for the ...
992 views

### Output first $n$ digits of $\pi^{1/\pi}$

This challenge is to produce the shortest code for the constant $\pi^{1/\pi}$. Your code must output the first $n$ consecutive digits of $\pi^{1/\pi}$, where $n$ is given in the input. ...
2k views

### To exponential digit growth and beyond!

Challenge Given a base $1 < b < 10$ and an index $t \ge 1$, output term $x_t$, defined as follows: $x_1 = 11_{10}$ $x_{i+1}$ is obtained by converting $x_i$ to base $b$ and then ...
2k views

### Surface of the 3x3x3 cube as a graph

Your task is to generate a graph with 54 vertices, each corresponds to a facet on a Rubik's cube. There is an edge between two vertices iff the corresponding facets share a side. Rules You may ...
2k views

### Split into three!

Given a string, you've to split it into groups of three characters (by padding _ at the end). Related, but still it's different. Sample I/O: ...
811 views

### Expand a hexagon

Given an ASCII art hexagon as input, output one whose sides are all one unit longer. ...
1k views

### Warped chessboard

This challenge is about building a chessboard in which the square size, instead of being constant across the board, follows a certain non-decreasing sequence, as described below. The board is defined ...
1k views

### Save my secrets!

I have so many secrets and nowhere to keep them! The goal is simple: write a program that lets you save a string and have it be protected by a password. The program will take an alias, password and (...
4k views

### pwaS eht tirsf dna tasl setterl fo hace dorw

Or, "Swap the first and last letters of each word" Your challenge is to, given a string of alphabetical ASCII characters as well as one other character to use as a delimiter (to separate each word), ...
4k views

### Gambler's Fallacy Dice

The gambler's fallacy is a cognitive bias where we mistakenly expect things that have occurred often to be less likely to occur in the future and things that have not occurred in a while to be more ...
292 views

### Convert a number into “bracket” numerals

"Bracket" numerals are a type of 'numerals' I made up once, and thought would be a nice challenge here. Basically, you convert the input number into base 6, and then transliterate the ...
4k views

### Parse a C++14 integer literal

According to http://en.cppreference.com/w/cpp/language/integer_literal, integer literals consist of a decimal/hex/octal/binary literal and a optional integer suffix, that is obviously completely ...
2k views

### Divisor Rich and Poor Numbers

Introduction In the strange world of integer numbers, divisors are like assets and they use to call "rich" the numbers having more divisors than their reversal, while they call "poor" the ones having ...
3k views

### ​Cuban​ ​Primes

Given a natural number $n$, return the $n$-th cuban prime. Cuban Primes A cuban prime is a prime number of the form $$p = \frac{x^3-y^3}{x-y}$$ where $y>0$ and $x = 1+y$ or $x = 2+y$ ...
295 views

### Golf my Ada arrays

Background Ada is a programming language that is not exactly known for its terseness. However, its array literal syntax can in theory allow for fairly terse array specifications. Here is a simple ...
295 views

### Ambassadors and Translators

Two ambassadors at a UN conference want to speak to each other, but unfortunately each one only speaks one language- and they're not the same language. Fortunately, they have access to several ...
393 views

### Find all $k$-smooth pairs

Introduction In number theory, we say a number is $k$-smooth when its prime factors are all at most $k$. For example, 2940 is 7-smooth because $2940=2^2\cdot3\cdot5\cdot7^2$. Here, we define a ...
3k views

### Program which behaves differently in/out of a debugger [closed]

The challenge is to write a deterministic program (any language/OS) which takes no arguments or other input and behaves differently in a debugger from how it behaves when not being debugged. For ...
1k views

### Automatically anti-predictably assemble an alliterative aria

Thanks to @ComradeSparklePony for the title. This challenge should be very simple. You are given three lists. The first is a list of first names, in title case. The second is a list of adjectives, ...
132 views

### Building a Structured Outline [closed]

In a fictional document management system, input documents are structured with weighted headings. Lowest weighted headings are the most important. This is a sample document: H1 All About Birds H2 ...
628 views

### Extrude the faces of a cube symmetrically along XYZ

Sandbox For the purposes of the current task, a cube of unit length is rendered in oblique projection with ASCII symbols as follows: ...
7k views

### As programmers say: Strive to be lazy

Story Have you seen this post from 9gag? Maybe you got the feeling to make your own sentences. But then you realize that you could just golf a script in half an hour, and you will never have to deal ...
217 views

### Country Code Transformations

Background and Motivation: IOC Country Codes are three letter abbreviations that are commonly used when broadcasting the Olympic Games. The last two letters of some codes overlap with the first two ...
2k views

### Make all the squares explode

You are given a square matrix of width $\ge2$, containing square numbers $\ge1$. Your task is to make all square numbers 'explode' until all of them have disappeared. You must print or return the ...
385 views

### Composite Factor Soup

Per the fundamental theorem of arithmetic, for a given number $n$, it is possible to find it's prime factors, and they are unique. Let's imagine we talk only of $n$ that is non-prime (composite). ...
672 views

### Output the date in the Mel calendar

The Mel calendar is used in the fictional world of Kaldia. Your goal is to convert dates into the Mel calendar. This calendar has 13 months of 28 days each, plus 1 or 2 extra days after the last ...
5k views

### Is it a Munchausen Number?

A Munchausen Number in base $b$, also known as a Perfect digit-to-digit invariant or PDDI is a peculiar type of positive integer where the sum of its base-$b$ digits raised to themselves is equal ...
199 views

### Roots of Arbitrary Numbers [closed]

One day, when I was bored in maths class, I learned of a neat trick for solving the real cube root of a number! Let's use the number $79,507$ as an example. First, take digit in the one's place ...
1k views

### Magical Modulo Squares

I'm a big fan of number theory. A big thing in number theory is modular arithmetic; the definition being $a\equiv b\mod m$ if and only if $m\mid a-b$. A fun thing to do is raising to powers: ...
402 views

### Find the area of the smallest rectangle to contain squares of sizes up to n

This is a sequence question of the usual type, as applied to OEIS sequence A038666. That is, do either of the following: Accept no or any input, and output A038666 until the heat death of the ...
3k views

### Convert Numbers To Emoji Math [closed]

In Emoji Math, a user created module for the video game Keep Talking And Nobody Explodes, numbers are written as strings of emoticons, where each emoticon represents a base 10 digit. Below is the ...
493 views

### Rock, Paper, Scissors, Lizard, Spock Tournament

Giving a challenge involving a Star Trek reference just after May the 4th may be frowned upon, but here goes. You, Luke, Anakin, Palpatine, Yoda and Han Solo are involved in an insane tournament of ...
661 views

### Determine if a grid contains another grid

Challenge Create a function takes in two 2-dimensional arrays of Characters (or Strings if the programming language does not have characters as a datatype) as inputs: a and b. If your language does ...
2k views

### Make me a minimum magic sum

Keeping this challenge short. You are given 4 numbers: p1, p2, p3 and p4. The magic sum of the numbers are defined as follows: ...
604 views

### Dihedral group D4 composition with custom labels

The dihedral group $D_4$ is the symmetry group of the square, that is the moves that transform a square to itself via rotations and reflections. It consists of 8 elements: rotations by 0, 90, 180, ...
2k views

### Hostile Divisor Numbers

Some divisors of positive integers really hate each other and they don't like to share one or more common digits. Those integers are called Hostile Divisor Numbers (HDN) Examples Number <...
2k views

### A factorization game

Input A single integer $1 \leq x \leq 10^{15}$. Output The maximum number of distinct positive integers that have the product $x$. Examples Input: 1099511627776. Output: 9. One possible ...
414 views

### Intercommunication between threads [closed]

So glad I found this cool site. Wanted to try sharing a coding challenge a friend gave me, an interview question. Usually it is written in java, but you can use whatever language you want, just have ...
154 views

### Words Everywhere

Given a list of words, output a square grid of characters, so that all the words can be read from the grid, by moving horizontally, vertically, or diagonally between characters, without reusing ...
525 views

### Make some Prime Squares!

What is a Prime Square? A Prime Square is a square where all four edges are different prime numbers. But which ones? And how do we construct them? Here is an example of a 4x4 Prime Square ...
1k views

### Shantae Dance Matching

In the original Shantae game, there are transformation dances that you have to input in time using the D-Pad, A, and B. If you complete a predefined sequence while dancing, you will transform into the ...
4k views

### I'm in your subnets, golfing your code

Challenge Given an IPv4 address in dotted-quad notation, and an IPv4 subnet in CIDR notation, determine if the ...
314 views

### Maximizing by swapping

Input An integer n in the range 100 to 10^18 and an integer k in the range 1 to 18, inclusive. The swap operation A swap chooses two digits at different positions and exchanges their positions, as ...
549 views

### Type-check an expression

Given an infix expression, determine whether all constants are of the same type. Operators will consist only of these dyadic operators: +-/* Your program or ...
3k views

### Upside-Down Pyramid Addition…REVERSED!

Upside-Down Pyramid Addition is the process of taking a list of numbers and consecutively adding them together until you reach one number. When given the numbers ...
Given some positive integer $n$ generate all derangements of $n$ objects. Details A derangement is a permutation with no fixed point. (This means in every derangement number $i$ cannot be in ...