A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.
Indicates that the challenge involves the manipulation of binary matrices, matrices whose elements are all one of two possible values, typically 1 and 0, or True and False.
Fractals are shapes that are self-similar and are usually quite detailed. Well-known fractal sets include the Mandelbrot set, Julia sets, and Phoenix sets. Tree-like fractal drawings are also common…
For challenges involving data on a hexagonal grid. Use this tag also for triangular grids, the dual of the hexagonal grid (that is, the vertices of the hexagonal grid form the faces of the triangular …
Challenges which involve computing probabilities for random variables and stochastic processes.
Abstract Algebra is the study of algebraic structures, including groups, rings, fields, vector spaces, and the like.
for challenges involving an output (graphical or ASCII-art) which changes with time.
For challenges involving cryptography, including things like ciphers and hashing algorithms
This challenge is related to the C language. Note that challenges that require the answers to be in a specific language are generally discouraged.
For challenges related to the subdivision of a set into smaller disjoint sets. This also includes the subdivision of ordered collections like lists, and non-discrete sets like intervals. Challenges sh…
Classification challenges involve grouping input data into certain classes based on the properties of that data.
for challenges involving the mathematical constant pi, the ratio of a circle's circumference to its diameter.
Puzzles involving cellular automata, such as Conway's Game of Life.
For challenges related to the different ways of expressing an integer as a sum of positive integers.
Related to chemistry or some aspect of chemistry
Metagolf is golfing the output of a metaprogram. A metaprogram produces a program which solves a given task, and the length of that output determines the score of the original program.
For challenges relating to manipulating and traversing the file system. This may include reading directory trees, creating, moving and deleting files or directories, reading or changing file permissio…
For challenges involving linear algebra, the mathematics of vector spaces and linear mappings between them.
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.
For challenges that involve partitioning a space (usually the plane) into small tiles without gaps (usually using a finite set of proto-tiles). See also [set-partitions].
exists for historical reasons. New challenges of the type previously posted under this tag are not welcome.
For challenges involving a keyboard or keyboard layouts, such as QWERTY and AZERTY.
for a challenge involving the mathematical operator of division or integer division
An answer-chaining challenge is a challenge where previous answers to the challenge influence how new answers are produced.
A problem whose scoring criterion involves running the output of a program through a large number of test cases.
for challenges relating to mazes, typically generating or navigating them. This often is used with the [ascii-art] tag, a common method of demonstrating the mazes
For challenges involving simulation.
a challenge to build objects (e.g. code, representation of real world objects) according to pre-defined rules and/or input (also often randomised).
This challenge is related to the Java language. Note that challenges that require the answers to be in a specific language are generally discouraged.
For challenges involving stack-like data structures (see tag wiki for details), including interpreters of stack-based programming languages and challenges specifically about call stacks.
A ragged list, also called a jagged list, is a list where each element can either be some terminal type (e.g. an integer) or another ragged list.
for challenges related to the functional programming paradigm.
A busy beaver maximises some property of the computation model (e.g. execution time, memory usage, output length) subject to the constraint that it must halt.
Set theory is the branch of mathematics that studies unordered collections of objects. Challenges with this tag will involve the manipulation or analysis of sets.
For challenges involving ways to organize data (hash maps, arrays, binary trees ...)
A programming puzzle includes a goal, a partially completed program, and rules outlining how the program can be modified. The program is specifically designed to make achieving the goal difficult. An …
for challenges involving John Conway's Game of Life.