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.
1088 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.
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…
595 questions
A competition to solve a particular problem through the usage and manipulation of arrays.
555 questions
For challenges which involve deciding whether or not the input meets certain criteria, and outputting some data, representing that decision.
529 questions
Challenges related to elementary arithmetic.
497 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…
397 questions
Number theory involves properties and relationships of numbers, primarily positive integers.
369 questions
For challenges involving the manipulation of integers.
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…
312 questions
intended to be solved by using, manipulating, or creating shapes or other geometric structures.
311 questions
Imposes a restriction on the source code used to solve the challenge, for example, having no numbers in the source code.
308 questions
For challenges involving combinatorics.
For questions asking for tips on golfing in a specific language, doing well in certain challenge tag, or improving a particular piece of code.
287 questions
For challenges about identifying and manipulating prime numbers
287 questions
Tasks involving random numbers and/or output.
286 questions
For challenges involving a grid.
282 questions
generally based upon, related to, or simulates a game or some portion of one.
261 questions
intended to be solved by using, manipulating, accepting as input, outputting, or calculating calendar dates or clock times.
251 questions
a program which produces its source as output. This tag indicates that the challenge is related to quines.
249 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.
215 questions
denotes challenges where parsing input is a large / the main part of the challenge.
194 questions
intended to be solved by sorting, ordering, or otherwise organizing some set of data.
181 questions
the base 2 number system. Use this tag for challenges involving base 2.
172 questions
a particular ordering of some list of objects. Problems tagged with permutation usually involve finding or generating permutations, including anagrams of text.
169 questions
For challenges regarding graphs, mathematical structures used to model relations between objects.
166 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…
158 questions
Conversion of numbers between positional numeral systems. Most common systems are decimal, binary, hexadecimal etc.
156 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…
150 questions
For challenges that involve the physical layout or physical manipulation of source-code.
148 questions
These challenges involve processing pre-existing image files, by altering them in some way, gathering statistics, or other image processing tasks.
125 questions
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