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.
11822 questions
A competition to solve a particular problem through the usage and manipulation of strings.
2170 questions
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.
1300 questions
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.
1201 questions
For challenges involving sequences, typically of numbers following some pattern.
920 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).
899 questions
A competition to solve a particular problem through the usage and manipulation of arrays.
799 questions
For challenges which involve deciding whether or not the input meets certain criteria, and outputting some data, representing that decision.
734 questions
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…
685 questions
Challenges related to elementary arithmetic.
542 questions
Number theory involves properties and relationships of numbers, primarily positive integers.
457 questions
For challenges involving the manipulation of integers.
432 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.
379 questions
This challenge is intended to be solved by using, manipulating, or creating shapes or other geometric structures.
370 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.
370 questions
For challenges involving combinatorics.
369 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…
346 questions
Tasks involving random numbers and/or output.
345 questions
For challenges about identifying and manipulating prime numbers
343 questions
Imposes a restriction on the source code used to solve the challenge, for example, having no numbers in the source code.
337 questions
This challenge is generally based upon, related to, or simulates a game or some portion of one.
309 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.
295 questions
This challenge is intended to be solved by using, manipulating, accepting as input, outputting, or calculating calendar dates or clock times.
279 questions
A quine is a program which produces its source as output. This tag indicates that the challenge is related to quines.
266 questions
denotes challenges where parsing input is a large / the main part of the challenge.
251 questions
For challenges about binary, or the base 2 number system.
232 questions
This challenge is intended to be solved by sorting, ordering, or otherwise organizing some set of data.
209 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…
204 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.
202 questions
For challenges regarding graphs, mathematical structures used to model relations between objects.
201 questions
For challenges that involve the physical layout or physical manipulation of source-code.
189 questions
Conversion of numbers between positional numeral systems. Most common systems are decimal, binary, hexadecimal etc.
188 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…
173 questions
For challenges which consist of two adversary (and asymmetric) sub-challenges.
155 questions
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