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.

Code-golf is a competition to solve a particular problem in the fewest bytes of source code.
A competition to solve a particular problem through the usage and manipulation of strings.
The challenge involves mathematics in some central way. Also consider using more specific tags, listed in the tag wiki info.
A competition to solve a particular problem through the usage and manipulation of numbers.
This challenge involves creating or parsing pictures using text characters as the paint. Typically this uses only 95 printable (from a total of 128) characters defined by the ASCII Standard from 1963.
A code challenge is a competition for creative ways to solve a programming puzzle with an objective winning criterion not covered by other scoring tags (e.g. code-golf).
876 questions
For challenges involving sequences, typically of numbers following some pattern.
A competition to solve a particular problem through the usage and manipulation of arrays.
For challenges which involve deciding whether or not the input meets certain criteria, and outputting some data, representing that decision.
Kolmogorov complexity, informally, is the amount of code it takes to describe or produce a constant object, such as a string or image. When posting a challenge in this category, please make sure it ad…
651 questions
Challenges related to elementary arithmetic.
526 questions
Number theory involves properties and relationships of numbers, primarily positive integers.
424 questions
A popularity-contest is a competition where the answer with the highest vote tally (upvotes minus downvotes) wins. As these are frequently closed, read the tag info and post your challenge to the sand…
400 questions
For challenges involving the manipulation of integers.
400 questions
For challenges involving a grid.
354 questions
For challenges involving combinatorics.
342 questions
This challenge is intended to be solved by using, manipulating, or creating shapes or other geometric structures.
342 questions
For questions asking for tips on golfing in a specific language, doing well in certain challenge tag, or improving a particular piece of code.
338 questions
This challenge involves drawing pictures on a screen or generating image files. For pure ASCII art contests, use [ascii-art] instead. If participants can choose between graphics and ASCII art, use bot…
331 questions
Tasks involving random numbers and/or output.
325 questions
Imposes a restriction on the source code used to solve the challenge, for example, having no numbers in the source code.
325 questions
For challenges about identifying and manipulating prime numbers
318 questions
This challenge is generally based upon, related to, or simulates a game or some portion of one.
293 questions
for challenges involving matrices. A matrix, also known as a 2D array, is a list of numbers arranged in a rectangle with rows and columns.
270 questions
This challenge is intended to be solved by using, manipulating, accepting as input, outputting, or calculating calendar dates or clock times.
268 questions
A quine is a program which produces its source as output. This tag indicates that the challenge is related to quines.
261 questions
denotes challenges where parsing input is a large / the main part of the challenge.
234 questions
For challenges regarding binary, or the base 2 number system. Also, use on challenges relating to binary, such as challenges about negabinary or similar systems. Do not use on generic [base-conversion…
200 questions
This challenge is intended to be solved by sorting, ordering, or otherwise organizing some set of data.
198 questions
For challenges regarding graphs, mathematical structures used to model relations between objects.
186 questions
A permutation is a particular ordering of some list of objects. Problems tagged with permutation usually involve finding or generating permutations, including anagrams of text.
184 questions
The winner of a fastest-code challenge is determined by the runtime performance of the submissions. For fairness, all submissions should be benchmarked on the same machine, which usually means all sub…
180 questions
Conversion of numbers between positional numeral systems. Most common systems are decimal, binary, hexadecimal etc.
178 questions
For challenges that involve the physical layout or physical manipulation of source-code.
176 questions
King-of-the-hill indicates a game where the submissions interact with and compete against each other in some form of game. Competitions which pit programs against each other without interaction should…
168 questions
For challenges which consist of two adversary (and asymmetric) sub-challenges.
142 questions
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