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.

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. Also consider using more specific tags: [number] [number-theory] [arithmetic] [combinatorics] [graph-theory] [geometry] [abstract-algebra].
intended to be solved by using, manipulating, accepting as input, or outputting numeric values.
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.
1076 questions
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).
For challenges involving some sort of sequence.
695 questions
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…
575 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.
Challenges related to elementary arithmetic.
488 questions
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…
396 questions
Number theory involves properties and relationships of numbers, primarily positive integers.
360 questions
For challenges involving the manipulation of integers.
320 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…
309 questions
intended to be solved by using, manipulating, or creating shapes or other geometric structures.
297 questions
Imposes a restriction on the source code used to solve the challenge, for example, having no numbers in the source code.
296 questions
For challenges involving combinatorics.
283 questions
Tasks involving random numbers and/or output.
283 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.
278 questions
For challenges about identifying and manipulating prime numbers
277 questions
For challenges involving a grid.
generally based upon, related to, or simulates a game or some portion of one.
256 questions
a program which produces its source as output. This tag indicates that the challenge is related to quines.
244 questions
intended to be solved by using, manipulating, accepting as input, outputting, or calculating calendar dates or clock times.
242 questions
a list of numbers arranged in a rectangle with rows and columns. In programming, it is also known as a 2D array. Use this tag if your challenge is about manipulating matrices.
201 questions
denotes challenges where parsing input is a large / the main part of the challenge.
188 questions
intended to be solved by sorting, ordering, or otherwise organizing some set of data.
179 questions
the base 2 number system. Use this tag for challenges involving base 2.
167 questions
a particular ordering of some list of objects. Problems tagged with permutation usually involve finding or generating permutations, including anagrams of text.
166 questions
For challenges regarding graphs, mathematical structures used to model relations between objects.
160 questions
Conversion of numbers between positional numeral systems. Most common systems are decimal, binary, hexadecimal etc.
154 questions
determined by the runtime performance of the submissions. For fairness, all submissions should be benchmarked on the same machine, which usually means all sub…
153 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…
147 questions
For challenges that involve the physical layout or physical manipulation of source-code.
144 questions
These challenges involve processing pre-existing image files, by altering them in some way, gathering statistics, or other image processing tasks.
124 questions
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