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.
related to the C language. Note that challenges that require the answers to be in a specific language are generally discouraged.
exists for historical reasons. New challenges of the type previously posted under this tag are not welcome.
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 …
won by the answer with the smallest asymptotic time complexity. For challenges based on actual runtime, use [fastest-code] instead.
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…
the study of algebraic structures, including groups, rings, fields, vector spaces, and the like.
For challenges that ask for a function or involve functions in some way. (Also known as methods or subroutines.)
For challenges involving polynomials, mathematical expressions that consist of variables and coefficients.
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…
For challenges involving a keyboard or keyboard layouts, such as QWERTY and AZERTY.
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.
related to the Java language. Note that challenges that require the answers to be in a specific language are generally discouraged.
Challenges with a spec which requires all answers to meet certain time complexity restrictions. This could be specific ("Your answer must be O(n^2) where n is the number of items in the input"), or at…
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 challenge to build objects (e.g. code, representation of real world objects) according to pre-defined rules and/or input (also often randomised).
for a challenge involving the mathematical operator of division or integer division
For challenges involving simulation.
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 …
Puzzles involving cellular automata, such as Conway's Game of Life.
For challenges involving linear algebra, the mathematics of vector spaces and linear mappings between them.
For challenges related to the processing and placement of whitespace characters (mainly, but not limited to spaces, tabs and line feeds), like challenges related to indentation. For challenges about t…
For challenges involving ways to organize data (data types, arrays, binary trees ...)
For challenges involving binary matrices. Binary matrices are matrices which only contain boolean (0 or 1) values. Operations on binary matrices are done with boolean algebra.
A problem whose scoring criterion involves running the output of a program through a large number of test cases.
the branch of mathematics that studies unordered collections of objects. Challenges with this tag will involve the manipulation or analysis of sets.
a challenge where previous answers to the challenge influence how new answers are produced.
Tasks involving using Stack Exchange API.
related to the C++ language. Note that challenges that require the answers to be in a specific language are generally discouraged.
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].
For challenges related to the different ways of expressing an integer as a sum of positive integers.