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.
1185 questions
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).
889 questions
For challenges involving sequences, typically of numbers following some pattern.
883 questions
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…
673 questions
Challenges related to elementary arithmetic.
536 questions
Number theory involves properties and relationships of numbers, primarily positive integers.
450 questions
For challenges involving the manipulation of integers.
417 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…
404 questions
For challenges involving a grid.
377 questions
This challenge is intended to be solved by using, manipulating, or creating shapes or other geometric structures.
362 questions
For challenges involving combinatorics.
360 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.
355 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…
343 questions
Tasks involving random numbers and/or output.
341 questions
For challenges about identifying and manipulating prime numbers
333 questions
Imposes a restriction on the source code used to solve the challenge, for example, having no numbers in the source code.
331 questions
This challenge is generally based upon, related to, or simulates a game or some portion of one.
303 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.
286 questions
This challenge is intended to be solved by using, manipulating, accepting as input, outputting, or calculating calendar dates or clock times.
274 questions
A quine is a program which produces its source as output. This tag indicates that the challenge is related to quines.
262 questions
denotes challenges where parsing input is a large / the main part of the challenge.
243 questions
For challenges about binary, or the base 2 number system.
223 questions
This challenge is intended to be solved by sorting, ordering, or otherwise organizing some set of data.
209 questions
For challenges regarding graphs, mathematical structures used to model relations between objects.
199 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.
196 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…
195 questions
For challenges that involve the physical layout or physical manipulation of source-code.
188 questions
Conversion of numbers between positional numeral systems. Most common systems are decimal, binary, hexadecimal etc.
182 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…
170 questions
For challenges which consist of two adversary (and asymmetric) sub-challenges.
149 questions
2 3 4 5