问:
Is this number a prime?
Believe it or not, we do not yet have a code golf challenge for a simple primality test. While it may not be the most interesting challenge, particularly for "usual" languages, it can be nontrivial in many languages.

Rosetta code features lists by language of idiomatic approaches to primality testing, one using the Miller-Rabin test specifically and another using trial division. However, "most idiomatic" often does not coincide with "shortest." In an effort to make Programming Puzzles and Code Golf the go-to site for code golf, this challenge seeks to compile a catalog of the shortest approach in every language, similar to "Hello, World!" and Golf you a quine for great good!.

Furthermore, the capability of implementing a primality test is part of our definition of programming language, so this challenge will also serve as a directory of proven programming languages.

Task

Write a full program that, given a strictly positive integer n as input, determines whether n is prime and prints a truthy or falsy value accordingly.

For the purpose of this challenge, an integer is prime if it has exactly two strictly positive divisors. Note that this excludes 1, who is its only strictly positive divisor.

Your algorithm must be deterministic (i.e., produce the correct output with probability 1) and should, in theory, work for arbitrarily large integers. In practice, you may assume that the input can be stored in your data type, as long as the program works for integers from 1 to 255.

Input

If your language is able to read from STDIN, accept command-line arguments or any other alternative form of user input, you can read the integer as its decimal representation, unary representation (using a character of your choice), byte array (big or little endian) or single byte (if this is your languages largest data type).

If (and only if) your language is unable to accept any kind of user input, you may hardcode the input in your program.

In this case, the hardcoded integer must be easily exchangeable. In particular, it may appear only in a single place in the entire program.

For scoring purposes, submit the program that corresponds to the input 1.

Output

Output has to be written to STDOUT or closest alternative.

If possible, output should consist solely of a truthy or falsy value (or a string representation thereof), optionally followed by a single newline.

The only exception to this rule is constant output of your language's interpreter that cannot be suppressed, such as a greeting, ANSI color codes or indentation.

Additional rules

This is not about finding the language with the shortest approach for prime testing, this is about finding the shortest approach in every language. Therefore, no answer will be marked as accepted.

Submissions in most languages will be scored in bytes in an appropriate preexisting encoding, usually (but not necessarily) UTF-8.

The language Piet, for example, will be scored in codels, which is the natural choice for this language.

Some languages, like Folders, are a bit tricky to score. If in doubt, please ask on Meta.

Unlike our usual rules, feel free to use a language (or language version) even if it's newer than this challenge. If anyone wants to abuse this by creating a language where the empty program performs a primality test, then congrats for paving the way for a very boring answer.

Note that there must be an interpreter so the submission can be tested. It is allowed (and even encouraged) to write this interpreter yourself for a previously unimplemented language.

If your language of choice is a trivial variant of another (potentially more popular) language which already has an answer (think BASIC or SQL dialects, Unix shells or trivial Brainfuck derivatives like Headsecks or Unary), consider adding a note to the existing answer that the same or a very similar solution is also the shortest in the other language.

Built-in functions for testing primality are allowed. This challenge is meant to catalog the shortest possible solution in each language, so if it's shorter to use a built-in in your language, go for it.

Unless they have been overruled earlier, all standard code-golf rules apply, including the http://meta.codegolf.stackexchange.com/q/1061.

As a side note, please don't downvote boring (but valid) answers in languages where there is not much to golf; these are still useful to this question as it tries to compile a catalog as complete as possible. However, do primarily upvote answers in languages where the author actually had to put effort into golfing the code.

Catalog

The Stack Snippet at the bottom of this post generates the catalog from the answers a) as a list of shortest solution per language and b) as an overall leaderboard.

To make sure that your answer shows up, please start your answer with a headline, using the following Markdown template:

```<code>## Language Name, N bytes
</code>```

where N is the size of your submission. If you improve your score, you can keep old scores in the headline, by striking them through. For instance:

```<code>## Ruby, <s>104</s> <s>101</s> 96 bytes
</code>```

If there you want to include multiple numbers in your header (e.g. because your score is the sum of two files or you want to list interpreter flag penalties separately), make sure that the actual score is the last number in the header:

```<code>## Perl, 43 + 2 (-p flag) = 45 bytes
</code>```

You can also make the language name a link which will then show up in the snippet:

```<code>## [><>](http://esolangs.org/wiki/Fish), 121 bytes
</code>```

 <link rel="stylesheet" type="text/css" href="//cdn.sstatic.net/codegolf/all.css?v=83c949450c8b">

Shortest Solution by Language

Language	User	Score

Leaderboard

	Author	Language	Size

{{PLACE}}	{{NAME}}	{{LANGUAGE}}	{{SIZE}}	Link

{{LANGUAGE}}	{{NAME}}	{{SIZE}}	Link

```

答:
PHP, 51 bytes

An alternative PHP answer, but required the GMP extension to be installed:

```<code><?=gmp_strval(gmp_nextprime($argv[1]-1))==$argv[1];
</code>```

Simply subtracts 1 from the input and compares the nextprime result against the input

Title: Is this number a prime?

Body:
PHP, 51 bytes

An alternative PHP answer, but required the GMP extension to be installed:

<?=gmp_strval(gmp_nextprime($argv[1]-1))==$argv[1];

Simply subtracts 1 from the input and compares the nextprime result against the input


问:
How many lights are on?
You are little speck on a Cartesian plane. Pondering your existence, you decide to roam around your plane and touch things. You notice that every coordinate pair you visit has a light switch. To entertain yourself, you decide to toggle every switch that you come across.

The Challenge: Create a program that will take an input of random length, using only the characters v,^,<, and >. These characters correspond to movements.

< moves you one unit to the left

^ moves you one unit up

> moves you one unit to the right

v moves you one unit down

Using this randomly generated input, calculate how many switches will be left in the ON position, assuming you start at (0,0), all lights begin in the OFF state, and you don't turn on any lights until you make your first move. (Meaning, if you start at (0,0), and move up 1 unit to (0,1), there will now be 1 light on). If you come across a switch that is on the ON position, it will be turned OFF.

Test cases:

```<code>v>v<^^<v<<^<^><<>^^>>><v>vv^v>v^><><<^>><<<vvv^vvv>v>>v><vv^^<<>vv^^>v^<>>^^<^^>^^v<^>^<vvv^v^v><^<<v<<>><<>v>>^><^>^^<>>>>vv>^<<^<<><vvv<v^>>vvv>v^>>><<v^>^^^^v>>^>^v>v<vv^<>^<<v>vv>><^^<^><vv^^v<v<v^^^>v<^vv^v<><vv^^^>v^>v>vv<<^><v<^v><<v^^v>>v<vv<><^^^v<^v><><<^^<>^>><^^^>vv^<>>>>^<^<<<<>>>v<<v<v<vv><<vv<vv<^v^^^>>vv<>v>><<<v^>vv><v<<<v<<>^vvv^<v^v>^^v^v><<v^>>>v<v<v^>>>v><>>>^<><<<<>vv>v><v>v><^v<>v>>>vv<<>^>^>v<^><^<^vv^><^^>v<^^v>v^v<^^^^vv<>v<>><v^^><>v<<<>v^<v^^><>^<>^<>><>^^<>^v><>>><v<^^>>v>^^^<v
</code>```

yields 125 lights on.

```<code>>>><^>>>^vv><^^v^<<<>>^<>>^<^>^<<^^v^<v^>>^<<><<>^v<^^^vv>v><^>>^<^<v><^v<^<<^^v><>>^v<^>^v<vvv<<<v^vv>>^vv>^^<>>vv>^<^>vv<>v^<^v<^^<v^^^<<^><><>^v>vvv<^vvv<vv><vv<^^v^^<^^>>><<<>^<>>><^<<<>><>^v><^^vv<>>><^^^<^>>>>v<v^><<>v<v<v^<<^><v^^><>v>^<>^^^vvv<v^>^^^^v>v<v>>>v^^<v<vv>><<>^vv><<vv<<>^^v>>v<^^v>><v<v<<>^^vv>>^v>v>v<>^>^v<>>><>v>v<<v<^<>>>vv>>v>^<>vv^v><><^v^>v<^^>v<^v>>v^>^>>v>v>^>^<^^>vv>>^vv<^><>^><<v^<><<^<^>^^vv^<<^^<^^v<v<>^>v>>>>>>vv<<v>^>vv^>^><^<^^><<vvvv>vvv<><<><v^vv><v^^<>^>><^vv<><>^>vv>>>vv^vv<<^v^^<<v^^>^>vvv<><<v>^>^>v<v>^<^^^^<^>^>><>>^^vv<>v<^>v><v<v^>>v<^v<vv>v^>v<v^<^^^^v<^<^<<v<<<v<v^^>vv^>><<<v>>^^^>^<^>>>v^v><^^vv^>><^^vv<vv<v^><>>^><<<>>^^v^v<<v^<vv^^^>><>>^v^^^>>^>^<<^>v>^^v>><>v>^>vv^^<vvvv<><^v>^><<>>><^<^v^<<vvv^v<<<<<><><<><><<v>v<v>v><^v^^vvv>><>^>^>^v<<vv^^^v^vv><v><><v<v<<>>>v<^<^v<<>^v<<^v<><>v>>^^>^<v^<<^v^^^vv>><v^<v>^v><^<>>>>^^<vv<>^^>^>v^v^^>><>^^<^v^<v<<v<^<<^^vv>v>^<vv<<^^v^vv^>^^<>v>^>^<>vv><v>>><<><<vv^^<vv<>>^v>^<<vv>^><<>^<v>v><<v^<v<><v>^<^<^><^^^^>>>^<>^^><>>v^<vv^<^<<vvvv>>>v^v>>^>v^><<>>v<>>^>><vvvvv<<vvvv<v>^v<vv^<>><<><v^^<^<v>^v<^<<>^v<v^<>v<<>^<<vvv><^><^^^<>>v^<<>vv><^^^>><^>v^v>v<v^>>v>>v>vv<<v<<vvv^^^>^<v^^<^<v<^<>>v^<<v>>v^><v<vvvvv^^^<v^^<><v<<^>>^><^<v^v^^>><v><>v>^<vvvv><<v^^v^>^>v>><>^^v>v^>vv^>v<^<<^vv^>vv^<v>^<v^<>^v>v^>v^<<>^^<^>^^>vv^>>vv>v>vvv><>^v<<<<v^>v^^v<><v<v>^<^><^><<v<>><<>v^^>>><<><>>><<>><v^^>><^>><^<>v^^vvv>v<^<<vv^>vv^><<>v><>^<>v^^v>^>v^<>^><v>^><<^v<v^^<v>><^^>>^<^<^v<v>^>^<^<v><><>>>><>^<^<v>v<v^>v><>v^>v^<<><^<>>v<^vv^^^>^<<<<>^>^<><^vvv>^^<v^v>v>v^v>v>>vv>^><>^vv>^<v<v^<>vv^<v<><>^>>vvv><>>^<<v^<<>^<v^>v<^^^<^<^^<>^>>v>^<v>vv<v^^>><<<<<>>v>^v>^>>>>v>>^^>^<<<^<<<v>>^><<<<^vv<<>^v<^>v^<v<<>v<>^<^<^<^<>>^^^vvv<v>^vv>^><^<v^>^v<v>><><vvv<^^>>v<^v>^>>>><v^<v^^<^^v<vvv<v>^^<<>><^<v^v<^vv>v>vv>^^<>^^^^>>^v><vv<<<v>^v^>>v^>><<<^v^v<<>><<vvvvv<v^vv>vvvv><v^v<^^^><vv^^<>><>><^>^^^^v>v><><v^<>^v<>^^<^^>^^^vvv>>vv^v^<v<vv^v>v>>>^v^^vv^<^v>v^v>>^v>v<v^<^^><vvv>><<>><>><v>v<^<v>>>>v^^v^^>^><<v><^<<>>v<>^^<<>vv^>>vv^^^v>>>^v^><v<<^>v<v><>>>^>>^<<>>^><<vv<^^>^^^v^^<>>>vv><<>v<><<<>v<<>>>v<>v<>^<vv^v<^^<<<v>^v>>^^>^><<^vv<><><>v>^v>^<>v>>^^^<^^>>vv>v<<<v^><<v><^v><>v<^<<^<>^vv>^><^^^^^<<v^^<>v>><^<v^^^vv>^v<>^<v<v>v>^><^<<^<>><^^>vv^<>^<>vv<>>v<vv^>><^^<^>v<><>vv<v<>>v><v^^^>^^^<<vv^><^^v>v>^<^>v^><<vvv>v^><vv<><^<><^>^v<><<v^<<><>^^^^<<^>>^>^v^>v>^<<^>vv^vv^v<>^<<^>v<^^<<v<v<<<^>vv^>><>v>><><v>v><v^><vvv>vv<<vvv>v^<<^v<^<><<^v>v<>>vv<<v^>v>v<<>>^vv^<^^^<^v>>^<vv>^<v>><>v>^^<<v^<>>>>>v^v>><>v^>>^<>>^<^vvv^^^<^v<><vvv^>^>v><<v>>^v>v<v>v^<v>v>^<>vvv>vvv^^<>vv>^^^^^>v<<^v<>>>><<<>>><vv>>^v^^v<v^>>>^>^v<^v>^v<>vv<><vvv^v<<<<v<vv>vv^<^vvv<^v>v^^vv<^>>>^^>>^^><>^>>v<>>>^^<<v<^<<<<<^^<v^^^<<>><<<^>^v^>vv<>>>^^v><<>^^^^<vvv><^^<>>>^><<^>><v>^<>^v^<vvvv^>>^><<>><^<v^>>vv^vv<^>>>><^>^v<^<v<^^<^<^><^<>>^<>v^v<<>v>v<>><<v<^v<<<^v<v<>><v<^<^>>v>v>><v^<v><>>>>>v^v>><^<^<v>><v^v>v<>v<v><<<>^^><>^^<^vv^^<>v><><><^>^^v^vv^<><>>>>v><>>^>^<<^<v<v^>v^^<v>>><<^^vv^^>><<^<vvvvv>><^>^>>^vv<><<>v>v^<<<^v<^^<<^vv>v<vvv><^v>vv^vvvv<^>^v^<<<<^v<<<>^vvv>^v><<>>v<v<^v^<>v>>^^v^vv>>>^v^^>>^<><><<<<^vv>>>>>v>v^>v<>><<<>^vv>^^^^<^^^>^^^^>^^^v^v><^>^>>>v<v<^<^^<<^v<<^<>vvv^^^^v^<<>vv>^^>>><^^v<^<<<v<>v<<><>v<><>^<v<<^>^^>><<v>^^><^^v<^<v^<^^<>^<>^v^>>^^v^v^<>v<>^<<<>^v^v>^<vvvv<>v<<>vv^<<>vv>>>>^<v><>>>v^><<>^v>><<>>^^v><^<>>vv^^^>vv^<^^v><v>>vvv^v<^v>v<<^^<>v^^^v^^>><v^>>v^v^vv<^>v^<^>^>v<v^><vvv^>^<>v<<^><^^<vv>v>>vv>v^>>^vvv>>v^>^^>vvv>>v><<>>^^v>v<v<><<<<^^v<^<>^v>><v^^^<>>vvv>v><<v>^^<^vvvv^v>v>^vv>^vv^^v><<>>^^>>v>>>^v><^>v<^^<>vv>v>v^^^>>^^^><<<<>>^>>^<^v<^<^<>^><v<<v>v<>^>>^<<v^^<v^vvvvv>>v^>>^^^<^^<><<><><>^v>vvv^>^^>v<^^>^<<^v^^^><>><<v<^^^<<<<>><>><<^^v><v^<<^v<v><<>^<v>^>^v>vv>><v^<^<v<v<v><^^^^>>><^<><^v^v<<<^>vv^<v^>^^v^>>><<<<^<>>><v>>>vv^>^^<v^v>>>v^<^<>vv>^v^^><<<v>v>v>><>>>v<^>^<>>^^<v^<<^<v^>><^v^><><v><><v^vvv<<>v>>><<><v>v<>>><^<^^v<v>^<<>^v>^>^>^^<^^><^>>>>><^^>vv>^<^^<><^>^<^^><^<v>v^>><^>^^^>>v^v<^>>^<v^<>^><><v>>^v<v^^^^v<^vv><^v>>^^^<>^<^<^>vv^v<<>vv>^<>v>^>^>vv^v<vv<^^^v<v>v>v^<^^^v><v<<<^^<><^^>>>><<^^v<<^>v<<vv^^^vv^vv^<v><>^v<v>>><vv^v<v^>>>>^<<<vv^>>v>^><<><<^<^><<vv^>v^>><>v^<<<>v^><>><<>>v><>v^<v><>^v>>><><>>>^vvv^v>vv>>>^^v^><<v<>>^^^v^^><<^v<><><v<<v<v<><<<v^<^^^<>v^^v<^^<<^>v<<v><^<<<<>><>^v>^<>^<^^v^vvv>^^<>^>><v^^vv^<>^<><<^^^v<^^^>>^^v>^>^<^>v><<^<>^v<><vv^vv<><<<<<<v<<v<<vv^<<^<^vvvv><v^v^v<>>>vvvvv^<vv^<^<>vv>^<><<v><>v^^<v<>>>vvv^><^<^>v^^<v>^<>>>^^v^<vv<<<<^><v<<<>v<<<v<>>^^^>^><>v>^v^>^<v^^><^v^^<^v^^>^v>>^^^<<><><<<>v>><^><>>>vvvv>v>>v>^^^^v<><vv<^<v^v>>^^vv<^>vvv>^v>>><v<v<v^<^>^^<vvv<vv<v>>^vv>^<<^<^<v>v^<vv^^^v>vv<v><v><v>^<v>>vv<>v>^^>v^^^<>v<>v^v<>^<><v><^>^<v^v><<^v^v^v<<v><<^^<^vv>^<^v><>v>><v^v^>><><><<<v<>v<^vv>v<v<<>^vvvvv^<<<^<vv><<><>v^<^v<<<^>v>v<v^<<^>v<<^<v><<<^>vv>v>^<^^v>>>><>vv>>vv>vvv<>^^<>^v^<>vvv<^^^vv>v><<<<vv^v><v^<^<<<><v<>^><<>^>v<^^<<>v>>v<<>><^^<<<^<^vv^^>v>v<>^^>>^v^vvv>^v^>v>>v>v>v>>vv^<><<<<>v^^>vv<^^v>>v<vv<^>>^<>^^v<><vv^<><v><v<<v^v<^^<^v^v<>v<<><vvv><<<^<^^<<>>^v>>>^v>>>v<>>^><<<><><<<v<vv<^<>v^^v^^>^<<^^^v^>^<<^>^>^>>>>v<v<v<>vv<<vv^<<^<vv>^^<^<<>><^v><><>^<v><v^>^v>^<^>^^><v><<^<v^^<<^><><v>v<>>><<^><v<^vvv^<<<>><<>^v^^><vv>vv<>^>^>vv<>v^<^<>vv><<>^<v<vv<^<^<><^vv<<^>>>v<>><<>>>^^^^<<^v>>v<vv>^^>v<v<vv^><<><>>>v>>^^v<^v^^>>v^<>>v^>><^<^^v<v<><<><>>^<>><^v<^^^^><>^>vv>>^vv<<>v<<<<<<><<<><<>><v><^^^<>>v<^><^vvv<>^>^^v>^<v><^v^vv^<<>v<<<<v>^vv>>v>vv<<^>^<>>vvv^<v<><>><>^^^^vvvvvvv<<>v<^><^^>vv^^<v<<^^<vvv<v<v<<>><<><v^^>><^<>^v^vv<<v<v<>><<>>>>>^vv<><v<>v><v>v>><v<v^vvvvv<><>v>>v<><<<^^<>^<^^<v>v^<vv>^vv^<>^<<^<vv><v<v>>v>^<>v^<<v^<v>^v<>><v>>>>^<<^^^v<^<>><^<><v>>vv^>^<^<^>>v^>^^^^>vvvvv>^v<^><^^<^^>^<^^^^^^^>v>>vv>v^^^v^^^<>v><^>>>v>^>^>^>vv<vv<^^>>^>>>v<>v><<^<<v^>^>>>>^^><^^<v<<<<>>v>v^v^^<>><v<^<<<<v^^^^<v<<<^>v>^^<vv<^^^^^v>^v^<v><>>^^>^v>^>^vv^v>v>v^>v>^>>^^^^>>^>>^><>><v>v>>><<^v^v^>^>^>>vv><<^>v<v<v^<<>>^v<<^v<<^><^>>^<v>^>vv>v>^^^>v^^<^<^^>vv>^^><v>>^v>^v<<^^^<<^v^>^<<^>vv^>>^<^v><<>v><^^^<^^>>vv>^vv>><^<<<^>vv^v>v<^<<<^<^<<><^^>>>v^<^^^>^<><^v>>^<<v<^v>>v^<^<^<^^^<v^><<vvv^<^v^vv^vv<v<<v<^<>^v>^^^<^^v<v<v><<<^<>^^^^v>v^v^v^v<v><v>>^v><vv^^^v>><<v^vvvv<<<^v<<><^>^<v^^v<>vvvv^vv<>^v<><>^^<>>vvv<^>><v^<<>v>v<>^v^>v^>><<>>^^<^v<>>^>^><>>^<v<v^^<^v><v^<v<><><^<<><v^v<<>vv<v<v<^>>><>vv^^<><<v<^^<<^<><^^^>^>>>^<^>>>^>><^^^<^v^^^v^v^v>v>v><vv>><vvv<<v><><^^>^v<v>><v><^><^<<>v^vv^v><^vv>^>>v<vv><^<^^v<^^vv<vv<v<v>v><v<vv<<>^^v^^v<<<^<>v^^^<><>>><^>v^^^v^vv<<<^>>v><^>v^<>>>>^<>^^vvv^^<><^>^^<><>^vvv^^<vv^>vv^^^^v<>vv<^^^v<<>><<vvvvv>v>^^^vv>><v><v<>vvvv<v^><^<>^>^<>v>v>v^vvvv<><^v>>>^^>><vvv<>^>^v^<vvv>v^vv^vv><>><>v^^v^vv<^v>vv>>v<v><^<<^v<>>^vv^<v>v><v>v>^v>^<v>^<<^>vv>v<^<^vv^<^><<<v<<^^vv<vvv><>v>v<vv^<><><^vvv>>vv<^^^v><^v><<^>^^v>^<>><v<>>^^<<<v><>^>^><vvvv<>^<<<><<<^<>>v^vv^>><^vv^^>^<v^<v>><^^>>>^v>^v<>^v<><^><vv>v^^^<^>>^<<^<^><<<^^<v<<^vv<^<>v<^<<^^<v<vv<<><v<v^<>^<>v>>v<^v>v<>^^vvv<>vv^v^<><v^vv^<^v^v><>^><v^<>>^^^<>>vv^<v>^^v><v<^>^^^^^^><>>vvv<<><><v<^>v<>v^v<<<<>v^>>>>^v>^^<v^>v><v^<^^v<<<<v<<<>^v<^>^v>v^^>v^^vvv>vv<>^>v><v<>^<vv><>>><<^>>><<v>v^^<^<<<<v^<>>>v<<<^v^vv<>^v>v<<<<>^^>><v><>v<v><^^>><>^>^>v>>><v>^vvvv<><><^>>^v^><<>^v<><><^><<<>v^^>v>^>v^<v^vv<>><^vv^^>^^><vv<<>v>v^^>><v^>^<^<>>>vv<>^>v>v^<>v<^<<v>>>^<>v^>v>>vv^^<>>v<v<<^<>v>v^<^^^>v^^>v>v>vv<^<v>v^^><<<v<><>^^<>v>v>^^v>v>v^v>>^<v^v>><>^^>^<>>>^vv^><v^<^>v^>^v><^>^^^vv^^v<>vv<>>^><<^v>^v^>>v>^v^<<^^^vv<<vvv>^vv^v<<<v^^<<><vv<>>^^vv>^^^vv>><><v>v<^v^>>>vv^><>><v<^v<>^><v<^^^^>><^<>v>^v<^vv>v>v<^<>v>v>^<vv>v<^>vvv<v^<vv<vv<>v>^><v^v<>>>>>v>><^v<>v>^v><v^v^vv<>^<vvv^>><v^<vvv^^<^vvv^v^<>><v>v^^v<><>v^^^v<<<^><v<<<>><<vv<<><vvv^v>>v^v<v^>>><<v<>^v><>vv<<v>v^vv>v^v<^<vv<><><^v>^<vv>v^^>>^^^><vv<><^>>>^<v^<<^^>^>vv^><v<vvv>^^>>>^><<vv>vv>^<>>^^><^v><<>^<<<v^>^
</code>```

yields 1408 lights on.

To generate input, you may use the following Python script:

import random
length = random.randint(15, 10000)
walk = ''
chars = ['v', '<', '>', '^']
for i in range(length):
    walk += random.choice(chars)
print(walk)
```

Standard code-golf scoring, winner is the smallest number of bytes.

ContentLicense: CC BY-SA 3.0

Title: How many lights are on?

Body:
Perl, <s>102 98 91</s> 90 (89 + -n) bytes

perl -nE '$i=ord()%5,$x+=(-1..1)[$i],$y+=((0)x3,1,-1)[$i],$p{$x,$y}^=1 for/./g;say~~grep$_,values%p'

Readable:

$_ = <>; # -n
for (/./g) {
    $i = ord() % 5;
    $x += (-1 .. 1)[$i];
    $y += ((0) x 3, 1, -1)[$i];
    $p{$x, $y} ^= 1;
}

say 0 + grep $_, values %p;

thanks Dada for -4 and -7


答:
C, 203 190 189 bytes

#define S(s)1-(*s%11<7)*2<<*s%11%2*16
char*t,*u;P,p,r,L,e;
f(char*s){for(P=L=0,t=s;*t;++t){P+=S(t);e=r=1;for(p=0,u=s;u<t;u++)e*=(p+=S(u))!=P;for(p=P;*++u;r^=p==P)p+=S(u);L+=e*r;}return L;}
```

O(n^2) with O(1) memory algorithm.

It loops over every position, checks if this position occurs earlier, and if not checks if this position occurs an even/odd amount of time afterwards, adding it to the total.

Title: How many lights are on?

Body:
You are little speck on a Cartesian plane. Pondering your existence, you decide to roam around your plane and touch things. You notice that every coordinate pair you visit has a light switch. To entertain yourself, you decide to toggle every switch that you come across.

The Challenge: Create a program that will take an input of random length, using only the characters v,^,<, and >. These characters correspond to movements.

< moves you one unit to the left

^ moves you one unit up

> moves you one unit to the right

v moves you one unit down

Using this randomly generated input, calculate how many switches will be left in the ON position, assuming you start at (0,0), all lights begin in the OFF state, and you don't turn on any lights until you make your first move. (Meaning, if you start at (0,0), and move up 1 unit to (0,1), there will now be 1 light on). If you come across a switch that is on the ON position, it will be turned OFF.

Test cases:

```<code>v>v<^^<v<<^<^><<>^^>>><v>vv^v>v^><><<^>><<<vvv^vvv>v>>v><vv^^<<>vv^^>v^<>>^^<^^>^^v<^>^<vvv^v^v><^<<v<<>><<>v>>^><^>^^<>>>>vv>^<<^<<><vvv<v^>>vvv>v^>>><<v^>^^^^v>>^>^v>v<vv^<>^<<v>vv>><^^<^><vv^^v<v<v^^^>v<^vv^v<><vv^^^>v^>v>vv<<^><v<^v><<v^^v>>v<vv<><^^^v<^v><><<^^<>^>><^^^>vv^<>>>>^<^<<<<>>>v<<v<v<vv><<vv<vv<^v^^^>>vv<>v>><<<v^>vv><v<<<v<<>^vvv^<v^v>^^v^v><<v^>>>v<v<v^>>>v><>>>^<><<<<>vv>v><v>v><^v<>v>>>vv<<>^>^>v<^><^<^vv^><^^>v<^^v>v^v<^^^^vv<>v<>><v^^><>v<<<>v^<v^^><>^<>^<>><>^^<>^v><>>><v<^^>>v>^^^<v
</code>```

yields 125 lights on.

```<code>>>><^>>>^vv><^^v^<<<>>^<>>^<^>^<<^^v^<v^>>^<<><<>^v<^^^vv>v><^>>^<^<v><^v<^<<^^v><>>^v<^>^v<vvv<<<v^vv>>^vv>^^<>>vv>^<^>vv<>v^<^v<^^<v^^^<<^><><>^v>vvv<^vvv<vv><vv<^^v^^<^^>>><<<>^<>>><^<<<>><>^v><^^vv<>>><^^^<^>>>>v<v^><<>v<v<v^<<^><v^^><>v>^<>^^^vvv<v^>^^^^v>v<v>>>v^^<v<vv>><<>^vv><<vv<<>^^v>>v<^^v>><v<v<<>^^vv>>^v>v>v<>^>^v<>>><>v>v<<v<^<>>>vv>>v>^<>vv^v><><^v^>v<^^>v<^v>>v^>^>>v>v>^>^<^^>vv>>^vv<^><>^><<v^<><<^<^>^^vv^<<^^<^^v<v<>^>v>>>>>>vv<<v>^>vv^>^><^<^^><<vvvv>vvv<><<><v^vv><v^^<>^>><^vv<><>^>vv>>>vv^vv<<^v^^<<v^^>^>vvv<><<v>^>^>v<v>^<^^^^<^>^>><>>^^vv<>v<^>v><v<v^>>v<^v<vv>v^>v<v^<^^^^v<^<^<<v<<<v<v^^>vv^>><<<v>>^^^>^<^>>>v^v><^^vv^>><^^vv<vv<v^><>>^><<<>>^^v^v<<v^<vv^^^>><>>^v^^^>>^>^<<^>v>^^v>><>v>^>vv^^<vvvv<><^v>^><<>>><^<^v^<<vvv^v<<<<<><><<><><<v>v<v>v><^v^^vvv>><>^>^>^v<<vv^^^v^vv><v><><v<v<<>>>v<^<^v<<>^v<<^v<><>v>>^^>^<v^<<^v^^^vv>><v^<v>^v><^<>>>>^^<vv<>^^>^>v^v^^>><>^^<^v^<v<<v<^<<^^vv>v>^<vv<<^^v^vv^>^^<>v>^>^<>vv><v>>><<><<vv^^<vv<>>^v>^<<vv>^><<>^<v>v><<v^<v<><v>^<^<^><^^^^>>>^<>^^><>>v^<vv^<^<<vvvv>>>v^v>>^>v^><<>>v<>>^>><vvvvv<<vvvv<v>^v<vv^<>><<><v^^<^<v>^v<^<<>^v<v^<>v<<>^<<vvv><^><^^^<>>v^<<>vv><^^^>><^>v^v>v<v^>>v>>v>vv<<v<<vvv^^^>^<v^^<^<v<^<>>v^<<v>>v^><v<vvvvv^^^<v^^<><v<<^>>^><^<v^v^^>><v><>v>^<vvvv><<v^^v^>^>v>><>^^v>v^>vv^>v<^<<^vv^>vv^<v>^<v^<>^v>v^>v^<<>^^<^>^^>vv^>>vv>v>vvv><>^v<<<<v^>v^^v<><v<v>^<^><^><<v<>><<>v^^>>><<><>>><<>><v^^>><^>><^<>v^^vvv>v<^<<vv^>vv^><<>v><>^<>v^^v>^>v^<>^><v>^><<^v<v^^<v>><^^>>^<^<^v<v>^>^<^<v><><>>>><>^<^<v>v<v^>v><>v^>v^<<><^<>>v<^vv^^^>^<<<<>^>^<><^vvv>^^<v^v>v>v^v>v>>vv>^><>^vv>^<v<v^<>vv^<v<><>^>>vvv><>>^<<v^<<>^<v^>v<^^^<^<^^<>^>>v>^<v>vv<v^^>><<<<<>>v>^v>^>>>>v>>^^>^<<<^<<<v>>^><<<<^vv<<>^v<^>v^<v<<>v<>^<^<^<^<>>^^^vvv<v>^vv>^><^<v^>^v<v>><><vvv<^^>>v<^v>^>>>><v^<v^^<^^v<vvv<v>^^<<>><^<v^v<^vv>v>vv>^^<>^^^^>>^v><vv<<<v>^v^>>v^>><<<^v^v<<>><<vvvvv<v^vv>vvvv><v^v<^^^><vv^^<>><>><^>^^^^v>v><><v^<>^v<>^^<^^>^^^vvv>>vv^v^<v<vv^v>v>>>^v^^vv^<^v>v^v>>^v>v<v^<^^><vvv>><<>><>><v>v<^<v>>>>v^^v^^>^><<v><^<<>>v<>^^<<>vv^>>vv^^^v>>>^v^><v<<^>v<v><>>>^>>^<<>>^><<vv<^^>^^^v^^<>>>vv><<>v<><<<>v<<>>>v<>v<>^<vv^v<^^<<<v>^v>>^^>^><<^vv<><><>v>^v>^<>v>>^^^<^^>>vv>v<<<v^><<v><^v><>v<^<<^<>^vv>^><^^^^^<<v^^<>v>><^<v^^^vv>^v<>^<v<v>v>^><^<<^<>><^^>vv^<>^<>vv<>>v<vv^>><^^<^>v<><>vv<v<>>v><v^^^>^^^<<vv^><^^v>v>^<^>v^><<vvv>v^><vv<><^<><^>^v<><<v^<<><>^^^^<<^>>^>^v^>v>^<<^>vv^vv^v<>^<<^>v<^^<<v<v<<<^>vv^>><>v>><><v>v><v^><vvv>vv<<vvv>v^<<^v<^<><<^v>v<>>vv<<v^>v>v<<>>^vv^<^^^<^v>>^<vv>^<v>><>v>^^<<v^<>>>>>v^v>><>v^>>^<>>^<^vvv^^^<^v<><vvv^>^>v><<v>>^v>v<v>v^<v>v>^<>vvv>vvv^^<>vv>^^^^^>v<<^v<>>>><<<>>><vv>>^v^^v<v^>>>^>^v<^v>^v<>vv<><vvv^v<<<<v<vv>vv^<^vvv<^v>v^^vv<^>>>^^>>^^><>^>>v<>>>^^<<v<^<<<<<^^<v^^^<<>><<<^>^v^>vv<>>>^^v><<>^^^^<vvv><^^<>>>^><<^>><v>^<>^v^<vvvv^>>^><<>><^<v^>>vv^vv<^>>>><^>^v<^<v<^^<^<^><^<>>^<>v^v<<>v>v<>><<v<^v<<<^v<v<>><v<^<^>>v>v>><v^<v><>>>>>v^v>><^<^<v>><v^v>v<>v<v><<<>^^><>^^<^vv^^<>v><><><^>^^v^vv^<><>>>>v><>>^>^<<^<v<v^>v^^<v>>><<^^vv^^>><<^<vvvvv>><^>^>>^vv<><<>v>v^<<<^v<^^<<^vv>v<vvv><^v>vv^vvvv<^>^v^<<<<^v<<<>^vvv>^v><<>>v<v<^v^<>v>>^^v^vv>>>^v^^>>^<><><<<<^vv>>>>>v>v^>v<>><<<>^vv>^^^^<^^^>^^^^>^^^v^v><^>^>>>v<v<^<^^<<^v<<^<>vvv^^^^v^<<>vv>^^>>><^^v<^<<<v<>v<<><>v<><>^<v<<^>^^>><<v>^^><^^v<^<v^<^^<>^<>^v^>>^^v^v^<>v<>^<<<>^v^v>^<vvvv<>v<<>vv^<<>vv>>>>^<v><>>>v^><<>^v>><<>>^^v><^<>>vv^^^>vv^<^^v><v>>vvv^v<^v>v<<^^<>v^^^v^^>><v^>>v^v^vv<^>v^<^>^>v<v^><vvv^>^<>v<<^><^^<vv>v>>vv>v^>>^vvv>>v^>^^>vvv>>v><<>>^^v>v<v<><<<<^^v<^<>^v>><v^^^<>>vvv>v><<v>^^<^vvvv^v>v>^vv>^vv^^v><<>>^^>>v>>>^v><^>v<^^<>vv>v>v^^^>>^^^><<<<>>^>>^<^v<^<^<>^><v<<v>v<>^>>^<<v^^<v^vvvvv>>v^>>^^^<^^<><<><><>^v>vvv^>^^>v<^^>^<<^v^^^><>><<v<^^^<<<<>><>><<^^v><v^<<^v<v><<>^<v>^>^v>vv>><v^<^<v<v<v><^^^^>>><^<><^v^v<<<^>vv^<v^>^^v^>>><<<<^<>>><v>>>vv^>^^<v^v>>>v^<^<>vv>^v^^><<<v>v>v>><>>>v<^>^<>>^^<v^<<^<v^>><^v^><><v><><v^vvv<<>v>>><<><v>v<>>><^<^^v<v>^<<>^v>^>^>^^<^^><^>>>>><^^>vv>^<^^<><^>^<^^><^<v>v^>><^>^^^>>v^v<^>>^<v^<>^><><v>>^v<v^^^^v<^vv><^v>>^^^<>^<^<^>vv^v<<>vv>^<>v>^>^>vv^v<vv<^^^v<v>v>v^<^^^v><v<<<^^<><^^>>>><<^^v<<^>v<<vv^^^vv^vv^<v><>^v<v>>><vv^v<v^>>>>^<<<vv^>>v>^><<><<^<^><<vv^>v^>><>v^<<<>v^><>><<>>v><>v^<v><>^v>>><><>>>^vvv^v>vv>>>^^v^><<v<>>^^^v^^><<^v<><><v<<v<v<><<<v^<^^^<>v^^v<^^<<^>v<<v><^<<<<>><>^v>^<>^<^^v^vvv>^^<>^>><v^^vv^<>^<><<^^^v<^^^>>^^v>^>^<^>v><<^<>^v<><vv^vv<><<<<<<v<<v<<vv^<<^<^vvvv><v^v^v<>>>vvvvv^<vv^<^<>vv>^<><<v><>v^^<v<>>>vvv^><^<^>v^^<v>^<>>>^^v^<vv<<<<^><v<<<>v<<<v<>>^^^>^><>v>^v^>^<v^^><^v^^<^v^^>^v>>^^^<<><><<<>v>><^><>>>vvvv>v>>v>^^^^v<><vv<^<v^v>>^^vv<^>vvv>^v>>><v<v<v^<^>^^<vvv<vv<v>>^vv>^<<^<^<v>v^<vv^^^v>vv<v><v><v>^<v>>vv<>v>^^>v^^^<>v<>v^v<>^<><v><^>^<v^v><<^v^v^v<<v><<^^<^vv>^<^v><>v>><v^v^>><><><<<v<>v<^vv>v<v<<>^vvvvv^<<<^<vv><<><>v^<^v<<<^>v>v<v^<<^>v<<^<v><<<^>vv>v>^<^^v>>>><>vv>>vv>vvv<>^^<>^v^<>vvv<^^^vv>v><<<<vv^v><v^<^<<<><v<>^><<>^>v<^^<<>v>>v<<>><^^<<<^<^vv^^>v>v<>^^>>^v^vvv>^v^>v>>v>v>v>>vv^<><<<<>v^^>vv<^^v>>v<vv<^>>^<>^^v<><vv^<><v><v<<v^v<^^<^v^v<>v<<><vvv><<<^<^^<<>>^v>>>^v>>>v<>>^><<<><><<<v<vv<^<>v^^v^^>^<<^^^v^>^<<^>^>^>>>>v<v<v<>vv<<vv^<<^<vv>^^<^<<>><^v><><>^<v><v^>^v>^<^>^^><v><<^<v^^<<^><><v>v<>>><<^><v<^vvv^<<<>><<>^v^^><vv>vv<>^>^>vv<>v^<^<>vv><<>^<v<vv<^<^<><^vv<<^>>>v<>><<>>>^^^^<<^v>>v<vv>^^>v<v<vv^><<><>>>v>>^^v<^v^^>>v^<>>v^>><^<^^v<v<><<><>>^<>><^v<^^^^><>^>vv>>^vv<<>v<<<<<<><<<><<>><v><^^^<>>v<^><^vvv<>^>^^v>^<v><^v^vv^<<>v<<<<v>^vv>>v>vv<<^>^<>>vvv^<v<><>><>^^^^vvvvvvv<<>v<^><^^>vv^^<v<<^^<vvv<v<v<<>><<><v^^>><^<>^v^vv<<v<v<>><<>>>>>^vv<><v<>v><v>v>><v<v^vvvvv<><>v>>v<><<<^^<>^<^^<v>v^<vv>^vv^<>^<<^<vv><v<v>>v>^<>v^<<v^<v>^v<>><v>>>>^<<^^^v<^<>><^<><v>>vv^>^<^<^>>v^>^^^^>vvvvv>^v<^><^^<^^>^<^^^^^^^>v>>vv>v^^^v^^^<>v><^>>>v>^>^>^>vv<vv<^^>>^>>>v<>v><<^<<v^>^>>>>^^><^^<v<<<<>>v>v^v^^<>><v<^<<<<v^^^^<v<<<^>v>^^<vv<^^^^^v>^v^<v><>>^^>^v>^>^vv^v>v>v^>v>^>>^^^^>>^>>^><>><v>v>>><<^v^v^>^>^>>vv><<^>v<v<v^<<>>^v<<^v<<^><^>>^<v>^>vv>v>^^^>v^^<^<^^>vv>^^><v>>^v>^v<<^^^<<^v^>^<<^>vv^>>^<^v><<>v><^^^<^^>>vv>^vv>><^<<<^>vv^v>v<^<<<^<^<<><^^>>>v^<^^^>^<><^v>>^<<v<^v>>v^<^<^<^^^<v^><<vvv^<^v^vv^vv<v<<v<^<>^v>^^^<^^v<v<v><<<^<>^^^^v>v^v^v^v<v><v>>^v><vv^^^v>><<v^vvvv<<<^v<<><^>^<v^^v<>vvvv^vv<>^v<><>^^<>>vvv<^>><v^<<>v>v<>^v^>v^>><<>>^^<^v<>>^>^><>>^<v<v^^<^v><v^<v<><><^<<><v^v<<>vv<v<v<^>>><>vv^^<><<v<^^<<^<><^^^>^>>>^<^>>>^>><^^^<^v^^^v^v^v>v>v><vv>><vvv<<v><><^^>^v<v>><v><^><^<<>v^vv^v><^vv>^>>v<vv><^<^^v<^^vv<vv<v<v>v><v<vv<<>^^v^^v<<<^<>v^^^<><>>><^>v^^^v^vv<<<^>>v><^>v^<>>>>^<>^^vvv^^<><^>^^<><>^vvv^^<vv^>vv^^^^v<>vv<^^^v<<>><<vvvvv>v>^^^vv>><v><v<>vvvv<v^><^<>^>^<>v>v>v^vvvv<><^v>>>^^>><vvv<>^>^v^<vvv>v^vv^vv><>><>v^^v^vv<^v>vv>>v<v><^<<^v<>>^vv^<v>v><v>v>^v>^<v>^<<^>vv>v<^<^vv^<^><<<v<<^^vv<vvv><>v>v<vv^<><><^vvv>>vv<^^^v><^v><<^>^^v>^<>><v<>>^^<<<v><>^>^><vvvv<>^<<<><<<^<>>v^vv^>><^vv^^>^<v^<v>><^^>>>^v>^v<>^v<><^><vv>v^^^<^>>^<<^<^><<<^^<v<<^vv<^<>v<^<<^^<v<vv<<><v<v^<>^<>v>>v<^v>v<>^^vvv<>vv^v^<><v^vv^<^v^v><>^><v^<>>^^^<>>vv^<v>^^v><v<^>^^^^^^><>>vvv<<><><v<^>v<>v^v<<<<>v^>>>>^v>^^<v^>v><v^<^^v<<<<v<<<>^v<^>^v>v^^>v^^vvv>vv<>^>v><v<>^<vv><>>><<^>>><<v>v^^<^<<<<v^<>>>v<<<^v^vv<>^v>v<<<<>^^>><v><>v<v><^^>><>^>^>v>>><v>^vvvv<><><^>>^v^><<>^v<><><^><<<>v^^>v>^>v^<v^vv<>><^vv^^>^^><vv<<>v>v^^>><v^>^<^<>>>vv<>^>v>v^<>v<^<<v>>>^<>v^>v>>vv^^<>>v<v<<^<>v>v^<^^^>v^^>v>v>vv<^<v>v^^><<<v<><>^^<>v>v>^^v>v>v^v>>^<v^v>><>^^>^<>>>^vv^><v^<^>v^>^v><^>^^^vv^^v<>vv<>>^><<^v>^v^>>v>^v^<<^^^vv<<vvv>^vv^v<<<v^^<<><vv<>>^^vv>^^^vv>><><v>v<^v^>>>vv^><>><v<^v<>^><v<^^^^>><^<>v>^v<^vv>v>v<^<>v>v>^<vv>v<^>vvv<v^<vv<vv<>v>^><v^v<>>>>>v>><^v<>v>^v><v^v^vv<>^<vvv^>><v^<vvv^^<^vvv^v^<>><v>v^^v<><>v^^^v<<<^><v<<<>><<vv<<><vvv^v>>v^v<v^>>><<v<>^v><>vv<<v>v^vv>v^v<^<vv<><><^v>^<vv>v^^>>^^^><vv<><^>>>^<v^<<^^>^>vv^><v<vvv>^^>>>^><<vv>vv>^<>>^^><^v><<>^<<<v^>^
</code>```

yields 1408 lights on.

To generate input, you may use the following Python script:

import random
length = random.randint(15, 10000)
walk = ''
chars = ['v', '<', '>', '^']
for i in range(length):
    walk += random.choice(chars)
print(walk)
```

Standard code-golf scoring, winner is the smallest number of bytes.

Body:
C, 203 190 189 bytes

#define S(s)1-(*s%11<7)*2<<*s%11%2*16
char*t,*u;P,p,r,L,e;
f(char*s){for(P=L=0,t=s;*t;++t){P+=S(t);e=r=1;for(p=0,u=s;u<t;u++)e*=(p+=S(u))!=P;for(p=P;*++u;r^=p==P)p+=S(u);L+=e*r;}return L;}

O(n^2) with O(1) memory algorithm.

It loops over every position, checks if this position occurs earlier, and if not checks if this position occurs an even/odd amount of time afterwards, adding it to the total.


问:
All in all it's just, uh, another trick in code golf
The purpose of this challenge is to produce an ASCII version of the cover of this great album by the rock band Pink Floyd.

The brick junctions are made of characters _ and |. Bricks have width 7 and height 2 characters, excluding junctions. So the basic unit, including the junctions, is:

```<code>_________
|       |
|       |
_________
</code>```

Each row of bricks is offset by half a brick width (4 chars) with respect to the previous row:

```<code>________________________________________
  |       |       |       |       |
  |       |       |       |       |
________________________________________
      |       |       |       |       |
      |       |       |       |       |
________________________________________
  |       |       |       |       |
  |       |       |       |       |
</code>```

The wall is parameterized as follows. All parameters are measured in chars including junctions:

Horizontal offset of first row, F. This is the distance between the left margin and the first vertical junction of the upmost row. (Remember also the half-brick relative offset between rows). Its possible values are 0, 1, ..., 7.

Total width, W. This includes junctions. Its value is a positive integer.

Total height, H. This includes junctions. Its value is a positive integer.

The top of the wall always coincides with the top of a row. The bottom may be ragged (if the total height is not a multiple of 3). For example, here's the output for 6, 44, 11:

```<code>____________________________________________
      |       |       |       |       |
      |       |       |       |       |
____________________________________________
  |       |       |       |       |       |
  |       |       |       |       |       |
____________________________________________
      |       |       |       |       |
      |       |       |       |       |
____________________________________________
  |       |       |       |       |       |
</code>```

and a visual explanation of parameters:

```<code>          F=6
         ......
     .   ____________________________________________
     .         |       |       |       |       |
     .         |       |       |       |       |
     .   ____________________________________________
     .     |       |       |       |       |       |
H=11 .     |       |       |       |       |       |
     .   ____________________________________________
     .         |       |       |       |       |
     .         |       |       |       |       |
     .   ____________________________________________
     .     |       |       |       |       |       |

         ............................................
                             W=44
</code>```

Additional rules

You may provide a program or a function.

Input format is flexible as usual. Output may be through STDOUT or an argument returned by a function. In this case it may be a string with newlines or an array of strings.

Trailing spaces or newlines are allowed.

Shortest code in bytes wins.

Test cases

Inputs are in the order given above, that is: horizontal offset of first row, total width, total height.

```<code>6, 44, 11:
____________________________________________
      |       |       |       |       |
      |       |       |       |       |
____________________________________________
  |       |       |       |       |       |
  |       |       |       |       |       |
____________________________________________
      |       |       |       |       |
      |       |       |       |       |
____________________________________________
  |       |       |       |       |       |

2, 20, 10:
____________________
  |       |       |
  |       |       |
____________________
      |       |
      |       |
____________________
  |       |       |
  |       |       |
____________________

1, 1, 1:
_

1, 2, 3:
__
 |
 |

3, 80, 21:
________________________________________________________________________________
   |       |       |       |       |       |       |       |       |       |
   |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
       |       |       |       |       |       |       |       |       |       |
       |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
   |       |       |       |       |       |       |       |       |       |
   |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
       |       |       |       |       |       |       |       |       |       |
       |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
   |       |       |       |       |       |       |       |       |       |
   |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
       |       |       |       |       |       |       |       |       |       |
       |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
   |       |       |       |       |       |       |       |       |       |
   |       |       |       |       |       |       |       |       |       |
</code>```

ContentLicense: CC BY-SA 4.0

Body:
C, 92 bytes

b(f,w,h,y,x){for(y=0;y<h;y++,puts(""))for(x=0;x<w;x++)putchar(y%3?(x+y/3*4-f)%8?32:124:95);}

Invoke as b(F, W, H).


答:
C, 86 85 83 82 bytes

3 bytes saved thanks to Lynn.

1 byte saved thanks to charlie.

i;f(o,w,h){++w;for(i=0;++i<w*h;)putchar(i%w?i/w%3?i%w+i/w/3*4+~o&7?32:124:95:10);}
```

Title: All in all it's just, uh, another trick in code golf

Body:
The purpose of this challenge is to produce an ASCII version of the cover of this great album by the rock band Pink Floyd.

The brick junctions are made of characters _ and |. Bricks have width 7 and height 2 characters, excluding junctions. So the basic unit, including the junctions, is:

```<code>_________
|       |
|       |
_________
</code>```

Each row of bricks is offset by half a brick width (4 chars) with respect to the previous row:

```<code>________________________________________
  |       |       |       |       |
  |       |       |       |       |
________________________________________
      |       |       |       |       |
      |       |       |       |       |
________________________________________
  |       |       |       |       |
  |       |       |       |       |
</code>```

The wall is parameterized as follows. All parameters are measured in chars including junctions:

Horizontal offset of first row, F. This is the distance between the left margin and the first vertical junction of the upmost row. (Remember also the half-brick relative offset between rows). Its possible values are 0, 1, ..., 7.

Total width, W. This includes junctions. Its value is a positive integer.

Total height, H. This includes junctions. Its value is a positive integer.

The top of the wall always coincides with the top of a row. The bottom may be ragged (if the total height is not a multiple of 3). For example, here's the output for 6, 44, 11:

```<code>____________________________________________
      |       |       |       |       |
      |       |       |       |       |
____________________________________________
  |       |       |       |       |       |
  |       |       |       |       |       |
____________________________________________
      |       |       |       |       |
      |       |       |       |       |
____________________________________________
  |       |       |       |       |       |
</code>```

and a visual explanation of parameters:

```<code>          F=6
         ......
     .   ____________________________________________
     .         |       |       |       |       |
     .         |       |       |       |       |
     .   ____________________________________________
     .     |       |       |       |       |       |
H=11 .     |       |       |       |       |       |
     .   ____________________________________________
     .         |       |       |       |       |
     .         |       |       |       |       |
     .   ____________________________________________
     .     |       |       |       |       |       |

         ............................................
                             W=44
</code>```

Additional rules

You may provide a program or a function.

Input format is flexible as usual. Output may be through STDOUT or an argument returned by a function. In this case it may be a string with newlines or an array of strings.

Trailing spaces or newlines are allowed.

Shortest code in bytes wins.

Test cases

Inputs are in the order given above, that is: horizontal offset of first row, total width, total height.

```<code>6, 44, 11:
____________________________________________
      |       |       |       |       |
      |       |       |       |       |
____________________________________________
  |       |       |       |       |       |
  |       |       |       |       |       |
____________________________________________
      |       |       |       |       |
      |       |       |       |       |
____________________________________________
  |       |       |       |       |       |

2, 20, 10:
____________________
  |       |       |
  |       |       |
____________________
      |       |
      |       |
____________________
  |       |       |
  |       |       |
____________________

1, 1, 1:
_

1, 2, 3:
__
 |
 |

3, 80, 21:
________________________________________________________________________________
   |       |       |       |       |       |       |       |       |       |
   |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
       |       |       |       |       |       |       |       |       |       |
       |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
   |       |       |       |       |       |       |       |       |       |
   |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
       |       |       |       |       |       |       |       |       |       |
       |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
   |       |       |       |       |       |       |       |       |       |
   |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
       |       |       |       |       |       |       |       |       |       |
       |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
   |       |       |       |       |       |       |       |       |       |
   |       |       |       |       |       |       |       |       |       |
</code>```


问:
Find the minimum edit distance between two strings

Explanation

The edit distance between two strings is a function of the minimum possible number of insertions, deletions, or substitutions to convert one word into another word.

Insertions and deletions cost 1, and substitutions cost 2.

For example, the distance between AB and A is 1, because deletions cost 1 and the only edit needed is the deletion of the B character.

The distance between CAR and FAR is 2, because substitutions cost 2. Another way to look at this is one deletion and one insertion.

Rules

Given two input strings (supplied however is convenient in your language), your program must find the minimum edit distance between the two strings.

You may assume that the strings only contain the characters A-Z and have fewer than 100 characters and more than 0 characters.

This is code golf, so the shortest solution wins.

Sample Test Cases

```<code>ISLANDER, SLANDER
> 1
MART, KARMA
> 5
KITTEN, SITTING
> 5
INTENTION, EXECUTION
> 8
</code>```


答:
Pyth, <s>43</s> 27 bytes

I need to golf it heavily... the score is too shameful.

```<code>AQVE<*H?%N3X*8d+G*4/N3\|\_H
</code>```

Try it online already.

Input format

```<code>6,44
11
</code>```

Output format

```<code>____________________________________________
      |       |       |       |       |
      |       |       |       |       |
____________________________________________
  |       |       |       |       |       |
  |       |       |       |       |       |
____________________________________________
      |       |       |       |       |
      |       |       |       |       |
____________________________________________
  |       |       |       |       |       |
</code>```

Explanation

```<code>AQVE<*H?%N3X*8d+G*4/N3\|\_H   First two inputs as list in Q,
                              third input as E.

AQ                            Assign G to the first item in Q
                              and H to the second item in Q.
  VE                          For N from 0 to E-1:
                   /N3            N floor-div 3.
                                    if N gives a remainder of 3 or 4 or 5
                                    when divided by 6, this will be odd;
                                    otherwise, this will be even.
                 *4               Multiply by 4.
                                    if the above is odd, this will leave
                                    a remainder of 4 when divided by 8;
                                    otherwise, the remainder would be 0.
               +G                 Add G (as an offset).
           X*8d       \|          In the string "        " (*8d),
                                  replace (X) the character with the
                                  index above with "|" (modular indexing,
                                  hence the manipulation above).
       ?%N3             \_        If N%3 is non-zero, use the above;
                                  otherwise, use "_".
     *H                           The above repeated H times.
    <                     H       Take the first H characters of above.
                                  Implicitly print with newline.
</code>```

Body:
Pyth, <s>43</s> 27 bytes

I need to golf it heavily... the score is too shameful.

AQVE<*H?%N3X*8d+G*4/N3\|\_H

Try it online already.

Input format

6,44
11

Output format

____________________________________________
      |       |       |       |       |
      |       |       |       |       |
____________________________________________
  |       |       |       |       |       |
  |       |       |       |       |       |
____________________________________________
      |       |       |       |       |
      |       |       |       |       |
____________________________________________
  |       |       |       |       |       |

Explanation

AQVE<*H?%N3X*8d+G*4/N3\|\_H   First two inputs as list in Q,
                              third input as E.

AQ                            Assign G to the first item in Q
                              and H to the second item in Q.
  VE                          For N from 0 to E-1:
                   /N3            N floor-div 3.
                                    if N gives a remainder of 3 or 4 or 5
                                    when divided by 6, this will be odd;
                                    otherwise, this will be even.
                 *4               Multiply by 4.
                                    if the above is odd, this will leave
                                    a remainder of 4 when divided by 8;
                                    otherwise, the remainder would be 0.
               +G                 Add G (as an offset).
           X*8d       \|          In the string "        " (*8d),
                                  replace (X) the character with the
                                  index above with "|" (modular indexing,
                                  hence the manipulation above).
       ?%N3             \_        If N%3 is non-zero, use the above;
                                  otherwise, use "_".
     *H                           The above repeated H times.
    <                     H       Take the first H characters of above.
                                  Implicitly print with newline.


Body:
Perl, 63 bytes

#!perl -nl
$y+=print+map$y%3?$_++-$`&7?$":'|':_,($y%6&4)x$&for/ \d+/..$'

Counting the shebang as 2, input is taken from stdin, whitespace separated.

Sample Usage

$ echo 2 20 10 | perl bricks.pl
____________________
  |       |       |
  |       |       |
____________________
      |       |
      |       |
____________________
  |       |       |
  |       |       |
____________________


答:
Mathematica, 64 bytes

A port of Luis Mendo's MATL answer.

```<code>Count[{_,_?OddQ}]@Tally@Accumulate[I^Mod[ToCharacterCode@#,11]]&
</code>```

Title: How many lights are on?

Body:
Mathematica, 64 bytes

A port of Luis Mendo's MATL answer.

Count[{_,_?OddQ}]@Tally@Accumulate[I^Mod[ToCharacterCode@#,11]]&


问:
Alphabet to Number and Number to Alphabet

Challenge

In this challenge you have to take a number as input and output the corresponding letter of the alphabet, and vice versa. (1 <=> A, 2 <=> B) etc.

```<code>1 -> A
2 -> B
...
26 -> Z

A -> 1
B -> 2
...
Z -> 26
</code>```

Rules

This is code-golf, so shortest code in bytes wins.

The input will only consist of either an uppercase letter from A to Z or an integer from 1 to 26 inclusive.

Trailing whitespaces (space and newline) are allowed.

答:
R, 62 Bytes

```<code>f=function(x)ifelse(is.finite(x),LETTERS[x],which(LETTERS==x))
</code>```

Takes the input x and checks if it is finite, which is one byte shorter than checking if it is numeric and equivalent in this case. If yes, output the letter, if no, output the position in the alphabet equal to the character input.

Body:
R, 62 Bytes

f=function(x)ifelse(is.finite(x),LETTERS[x],which(LETTERS==x))

Takes the input x and checks if it is finite, which is one byte shorter than checking if it is numeric and equivalent in this case. If yes, output the letter, if no, output the position in the alphabet equal to the character input.


答:
Python 2, <s>93</s> 88 bytes

<s>2nd indentation level is tab</s> Saving some bytes thanks to Leaky Nun and some own modifications, also now correct offset:

def f(F,W,H):
 for h in range(H):print["_"*W,((("|"+7*" ")*W)[8-F+h%6/3*4:])[:W]][h%3>0]
```

<p>previous code:</p>

<pre class="lang-python prettyprint-override"><code>def f(F,W,H,x="|"+7*" "):
 for h in range(H):
    print ["_"*W,(x[F+4*(h%6>3):]+x*W)[:W]][h%3>0]
</code>```

Same length as unnamed lambda:

lambda F,W,H,x="|"+7*" ":"\n".join(["_"*W,(x[F+4*(h%6>3):]+x*W)[:W]][h%3>0]for h in range(H))
```

Body:
Python 2, <s>93</s> 88 bytes

<s>2nd indentation level is tab</s> Saving some bytes thanks to Leaky Nun and some own modifications, also now correct offset:

def f(F,W,H):
 for h in range(H):print["_"*W,((("|"+7*" ")*W)[8-F+h%6/3*4:])[:W]][h%3>0]

previous code:

def f(F,W,H,x="|"+7*" "):
 for h in range(H):
    print ["_"*W,(x[F+4*(h%6>3):]+x*W)[:W]][h%3>0]

Same length as unnamed lambda:

lambda F,W,H,x="|"+7*" ":"\n".join(["_"*W,(x[F+4*(h%6>3):]+x*W)[:W]][h%3>0]for h in range(H))


问:
Random Golf of the Day #7: A distinctly random character

About the Series

This is a guest entry for the Random Golf of the Day series.

First off, you may treat this like any other code golf challenge, and answer it without worrying about the series at all. However, there is a leaderboard across all challenges. You can find the leaderboard along with some more information about the series in the first post.

Input

No input is taken.

Output

A single letter of the alphabet (case irrelevant), with an optional trailing newline. Each letter must have non-zero probability of being chosen, and all 26 probabilities must be distinct. To remove all ambiguity: Distinct means that there must not be two probabilities that are equal to each other.

Scoring

This is code golf. Shortest code in bytes wins.

A valid entry is a full program or function that has zero probability of not terminating.

Alphabet

To avoid confusion, the particular alphabet to be used is the Latin alphabet:

Either

```<code>ABCDEFGHIJKLMNOPQRSTUVWXYZ
</code>```

or

```<code>abcdefghijklmnopqrstuvwxyz
</code>```

You may choose to output upper case or lower case. Alternatively, you may choose to output different cases on different runs if that helps. The probability for a given letter is the probability of that letter appearing in either case (upper or lower).

Explanation

As it won't be at all obvious from the output, please include a clear explanation of how you achieved the 26 distinct probabilities.

Leaderboard

(from here)

var QUESTION_ID=89621,OVERRIDE_USER=20283;function answersUrl(e){return"https://api.stackexchange.com/2.2/questions/"+QUESTION_ID+"/answers?page="+e+"&pagesize=100&order=desc&sort=creation&site=codegolf&filter="+ANSWER_FILTER}function commentUrl(e,s){return"https://api.stackexchange.com/2.2/answers/"+s.join(";")+"/comments?page="+e+"&pagesize=100&order=desc&sort=creation&site=codegolf&filter="+COMMENT_FILTER}function getAnswers(){jQuery.ajax({url:answersUrl(answer_page++),method:"get",dataType:"jsonp",crossDomain:!0,success:function(e){answers.push.apply(answers,e.items),answers_hash=[],answer_ids=[],e.items.forEach(function(e){e.comments=[];var s=+e.share_link.match(/\d+/);answer_ids.push(s),answers_hash[s]=e}),e.has_more||(more_answers=!1),comment_page=1,getComments()}})}function getComments(){jQuery.ajax({url:commentUrl(comment_page++,answer_ids),method:"get",dataType:"jsonp",crossDomain:!0,success:function(e){e.items.forEach(function(e){e.owner.user_id===OVERRIDE_USER&&answers_hash[e.post_id].comments.push(e)}),e.has_more?getComments():more_answers?getAnswers():process()}})}function getAuthorName(e){return e.owner.display_name}function process(){var e=[];answers.forEach(function(s){var r=s.body;s.comments.forEach(function(e){OVERRIDE_REG.test(e.body)&&(r="
"+e.body.replace(OVERRIDE_REG,"")+"
")});var a=r.match(SCORE_REG);a&&e.push({user:getAuthorName(s),size:+a[2],language:a[1],link:s.share_link})}),e.sort(function(e,s){var r=e.size,a=s.size;return r-a});var s={},r=1,a=null,n=1;e.forEach(function(e){e.size!=a&&(n=r),a=e.size,++r;var t=jQuery("#answer-template").html();t=t.replace("{{PLACE}}",n+".").replace("{{NAME}}",e.user).replace("{{LANGUAGE}}",e.language).replace("{{SIZE}}",e.size).replace("{{LINK}}",e.link),t=jQuery(t),jQuery("#answers").append(t);var o=e.language;/s.lang?1:e.lang<s.lang?-1:0});for(var c=0;c<t.length;++c){var i=jQuery("#language-template").html(),o=t[c];i=i.replace("{{LANGUAGE}}",o.lang).replace("{{NAME}}",o.user).replace("{{SIZE}}",o.size).replace("{{LINK}}",o.link),i=jQuery(i),jQuery("#languages").append(i)}}var ANSWER_FILTER="!t)IWYnsLAZle2tQ3KqrVveCRJfxcRLe",COMMENT_FILTER="!)Q2B_A2kjfAiU78X(md6BoYk",answers=[],answers_hash,answer_ids,answer_page=1,more_answers=!0,comment_page;getAnswers();var SCORE_REG=/<h\d>\s*([^\n,]*[^\s,]),.*?(\d+)(?=[^\n\d<>]*(?:<(?:s>[^\n<>]*<\/s>|[^\n<>]+>)[^\n\d<>]*)*<\/h\d>)/,OVERRIDE_REG=/^Override\s*header:\s*/i;```
<pre class="snippet-code-css lang-css prettyprint-override"><code>body{text-align:left!important}#answer-list,#language-list{padding:10px;width:290px;float:left}table thead{font-weight:700}table td{padding:5px}</code>```

 <link rel="stylesheet" type="text/css" href="//cdn.sstatic.net/codegolf/all.css?v=83c949450c8b">

Leaderboard

	Author	Language	Size

Winners by Language

Language	User	Score

{{PLACE}}	{{NAME}}	{{LANGUAGE}}	{{SIZE}}	Link

{{LANGUAGE}}	{{NAME}}	{{SIZE}}	Link

```
</div>
</div>
</p>

<p><strong>The first post of the series also generates an overall leaderboard.</strong></p>

<p>To make sure that your answers show up, please start every answer with a headline, using the following Markdown template:</p>

```## Language Name, N bytes
```

<p>where <code>N</code> is the size of your submission. If you improve your score, you <em>can</em> keep old scores in the headline, by striking them through. For instance:</p>

```## Ruby, <s>104</s> <s>101</s> 96 bytes
```

(The language is not currently shown, but the snippet does require and parse it, and I may add a by-language leaderboard in the future.)

答:
Matlab, <s>24</s> 18 bytes

<s>char(floor(26*rand^2+65))</s>

it looks like using floor(x) isn't necessary as char also takes non-integer inputs

```<code>char(25*rand^2+65)
</code>```

not using ['' x] instead of char(x) so I won't get warning: implicit conversion from numeric to char for "purer" output.

rand yields a uniformly distributed random number in the interval (0,1) but rand^2 isn't uniformy distributed anymore, the probability density function follows ,  see here.

with (b-a)*rand+a one can shift the interval of the distribution from (0,1) to (a,b), this also works with rand^2.

<s>because i use floor i need to stretch the interval to (65,91) so i don't lose "Z"</s>

It might no be the shortest answer but i like the approach with using a uniform random distribution to get a non-uniform random distribution.

Below is the count for each generated numbers after 20000 iterations (using my first version of my answer).

Body:
Matlab, <s>24</s> 18 bytes

<s>char(floor(26*rand^2+65))</s>

it looks like using floor(x) isn't necessary as char also takes non-integer inputs

char(25*rand^2+65)

not using ['' x] instead of char(x) so I won't get warning: implicit conversion from numeric to char for "purer" output.

rand yields a uniformly distributed random number in the interval (0,1) but rand^2 isn't uniformy distributed anymore, the probability density function follows ,  see here.

with (b-a)*rand+a one can shift the interval of the distribution from (0,1) to (a,b), this also works with rand^2.

<s>because i use floor i need to stretch the interval to (65,91) so i don't lose "Z"</s>

It might no be the shortest answer but i like the approach with using a uniform random distribution to get a non-uniform random distribution.

Below is the count for each generated numbers after 20000 iterations (using my first version of my answer).


问:
Print numbers from 1 to 10
This might be a very simple challenge, but I am surprised it hasn't been done on code-golf yet:

Print all Integers from 1 to 10 inclusive in ascending order to standard output.

Your output format can be whatever your language supports. This includes arbitrary separators (commas, semicolons, newlines, combinations of those, etc., but no digits), and prefixes and postfixes (like [...]). However, you may not output any other numbers than 1 through 10. Your program may not take any input. Standard loopholes are disallowed.

This is code-golf, so shortest answer in bytes wins!

Leaderboard

var QUESTION_ID=86075,OVERRIDE_USER=42570;function answersUrl(e){return"https://api.stackexchange.com/2.2/questions/"+QUESTION_ID+"/answers?page="+e+"&pagesize=100&order=desc&sort=creation&site=codegolf&filter="+ANSWER_FILTER}function commentUrl(e,s){return"https://api.stackexchange.com/2.2/answers/"+s.join(";")+"/comments?page="+e+"&pagesize=100&order=desc&sort=creation&site=codegolf&filter="+COMMENT_FILTER}function getAnswers(){jQuery.ajax({url:answersUrl(answer_page++),method:"get",dataType:"jsonp",crossDomain:!0,success:function(e){answers.push.apply(answers,e.items),answers_hash=[],answer_ids=[],e.items.forEach(function(e){e.comments=[];var s=+e.share_link.match(/\d+/);answer_ids.push(s),answers_hash[s]=e}),e.has_more||(more_answers=!1),comment_page=1,getComments()}})}function getComments(){jQuery.ajax({url:commentUrl(comment_page++,answer_ids),method:"get",dataType:"jsonp",crossDomain:!0,success:function(e){e.items.forEach(function(e){e.owner.user_id===OVERRIDE_USER&&answers_hash[e.post_id].comments.push(e)}),e.has_more?getComments():more_answers?getAnswers():process()}})}function getAuthorName(e){return e.owner.display_name}function process(){var e=[];answers.forEach(function(s){var r=s.body;s.comments.forEach(function(e){OVERRIDE_REG.test(e.body)&&(r="
"+e.body.replace(OVERRIDE_REG,"")+"
")});var a=r.match(SCORE_REG);a&&e.push({user:getAuthorName(s),size:+a[2],language:a[1],link:s.share_link})}),e.sort(function(e,s){var r=e.size,a=s.size;return r-a});var s={},r=1,a=null,n=1;e.forEach(function(e){e.size!=a&&(n=r),a=e.size,++r;var t=jQuery("#answer-template").html();t=t.replace("{{PLACE}}",n+".").replace("{{NAME}}",e.user).replace("{{LANGUAGE}}",e.language).replace("{{SIZE}}",e.size).replace("{{LINK}}",e.link),t=jQuery(t),jQuery("#answers").append(t);var o=e.language;/s.lang?1:e.lang<s.lang?-1:0});for(var c=0;c<t.length;++c){var i=jQuery("#language-template").html(),o=t[c];i=i.replace("{{LANGUAGE}}",o.lang).replace("{{NAME}}",o.user).replace("{{SIZE}}",o.size).replace("{{LINK}}",o.link),i=jQuery(i),jQuery("#languages").append(i)}}var ANSWER_FILTER="!t)IWYnsLAZle2tQ3KqrVveCRJfxcRLe",COMMENT_FILTER="!)Q2B_A2kjfAiU78X(md6BoYk",answers=[],answers_hash,answer_ids,answer_page=1,more_answers=!0,comment_page;getAnswers();var SCORE_REG=/<h\d>\s*([^\n,]*[^\s,]),.*?(\d+)(?=[^\n\d<>]*(?:<(?:s>[^\n<>]*<\/s>|[^\n<>]+>)[^\n\d<>]*)*<\/h\d>)/,OVERRIDE_REG=/^Override\s*header:\s*/i;```
<pre class="snippet-code-css lang-css prettyprint-override"><code>body{text-align:left!important}#answer-list,#language-list{padding:10px;width:290px;float:left}table thead{font-weight:700}table td{padding:5px}</code>```

 <link rel="stylesheet" type="text/css" href="//cdn.sstatic.net/codegolf/all.css?v=83c949450c8b">

Leaderboard

	Author	Language	Size

Winners by Language

Language	User	Score

{{PLACE}}	{{NAME}}	{{LANGUAGE}}	{{SIZE}}	Link

{{LANGUAGE}}	{{NAME}}	{{SIZE}}	Link

```

答:
T-SQL, 53 46 Bytes

Saved 7 bytes thanks to @t-clausen.dk

```<code>DECLARE @ INT=1z:PRINT @ SET @+=1IF @<11GOTO z
</code>```

Also 17 bytes (though it feels like cheating):

```<code>PRINT 12345678910
</code>```

Title: Print numbers from 1 to 10

Body:
T-SQL, 53 46 Bytes

Saved 7 bytes thanks to @t-clausen.dk

DECLARE @ INT=1z:PRINT @ SET @+=1IF @<11GOTO z

Also 17 bytes (though it feels like cheating):

PRINT 12345678910


答:
PowerShell v2+, 42 bytes

```<code>param($n)([char](64+$n),(+$n-64))[$n-ge65]
</code>```

Takes input $n (as an integer or an explicit char) and uses a pseudo-ternary to choose between two elements of an array. The conditional is $n-ge65 (i.e., is the input ASCII A or greater). If so, we simply cast the input as an int and subtract 64. Otherwise, we add 64 to the input integer, and cast it as a [char]. In either case, the result is left on the pipeline and printing is implicit.

Examples

```<code>PS C:\Tools\Scripts\golfing> ([char[]](65..90)|%{.\alphabet-to-number.ps1 $_})-join','
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26

PS C:\Tools\Scripts\golfing> (1..26|%{.\alphabet-to-number.ps1 $_})-join','
A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z
</code>```

Title: Alphabet to Number and Number to Alphabet

Body:
Challenge

In this challenge you have to take a number as input and output the corresponding letter of the alphabet, and vice versa. (1 <=> A, 2 <=> B) etc.

```<code>1 -> A
2 -> B
...
26 -> Z

A -> 1
B -> 2
...
Z -> 26
</code>```

Rules

This is code-golf, so shortest code in bytes wins.

The input will only consist of either an uppercase letter from A to Z or an integer from 1 to 26 inclusive.

Trailing whitespaces (space and newline) are allowed.

Body:
PowerShell v2+, 42 bytes

param($n)([char](64+$n),(+$n-64))[$n-ge65]

Takes input $n (as an integer or an explicit char) and uses a pseudo-ternary to choose between two elements of an array. The conditional is $n-ge65 (i.e., is the input ASCII A or greater). If so, we simply cast the input as an int and subtract 64. Otherwise, we add 64 to the input integer, and cast it as a [char]. In either case, the result is left on the pipeline and printing is implicit.

Examples

PS C:\Tools\Scripts\golfing> ([char[]](65..90)|%{.\alphabet-to-number.ps1 $_})-join','
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26

PS C:\Tools\Scripts\golfing> (1..26|%{.\alphabet-to-number.ps1 $_})-join','
A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z


答:
Javascript <s>86</s> <s>77</s> <s>66</s> 60 bytes

```<code>i=>typeof i<'s'?String.fromCharCode(i+64):i.charCodeAt(0)-64
</code>```

saved 7 bytes after comments about using arrow functions

saved another 11 bytes by removing return / brackets  as noted by @manatwork

saved another 6 bytes thanks to @manatwork

Body:
Javascript <s>86</s> <s>77</s> <s>66</s> 60 bytes

i=>typeof i<'s'?String.fromCharCode(i+64):i.charCodeAt(0)-64

saved 7 bytes after comments about using arrow functions

saved another 11 bytes by removing return / brackets  as noted by @manatwork

saved another 6 bytes thanks to @manatwork


问:
Hello World 0.0!

 source: Dilbert, September 8, 1992

I'm hoping to add a new twist on the classic "Hello World!" program.

Code a program that outputs Hello World! without:

String/Character literals

Numbers (any base)

Pre-built functions that return "Hello World!"

RegEx literals

With the exceptions of "O"† and 0.

†"O" is capitalized, "o" is not acceptable.

答:
Clojure, 19 bytes

Since I am not allowed to comment (yet) both of atrociously long Clojure answers, here is mine:

```<code>(pr 'Hello 'World!)
</code>```

3 bytes shorter than print

Title: Hello World 0.0!

Body:
Clojure, 19 bytes

Since I am not allowed to comment (yet) both of atrociously long Clojure answers, here is mine:

(pr 'Hello 'World!)

3 bytes shorter than print


答:
Dyalog APL, 14 bytes

{0::⎕A⍳⍵
⍵⊃⎕A}
```

0:: if any error happens:

 ⎕A⍳⍵ return the index of the argument in the alphabet

⍵⊃⎕A use the argument to pick an element from the alphabet (errors if the argument is character)

TryAPL online!

Body:
Dyalog APL, 14 bytes

{0::⎕A⍳⍵
⍵⊃⎕A}

0:: if any error happens:

 ⎕A⍳⍵ return the index of the argument in the alphabet

⍵⊃⎕A use the argument to pick an element from the alphabet (errors if the argument is character)

TryAPL online!


问:
Print/Output all positive numbers in which every multi-digit substring in its decimal representation is also prime.

Task

Your task is to print or output all positive numbers in which every multi-digit substring in its decimal representation is also prime. If the number has at least 2 digits, this would imply that the number itself also needs to be prime.

Example

6197 is in the sequence because every multi-digit substring in 6197 is prime, namely: 61, 19, 97, 619, 197, 6197 (itself).

Note that 6 is not a prime but 6197 is still in the sequence because 6 is not a multi-digit substring of 6197.

8 is also in the sequence because every multi-digit substring in 8 is prime. There is no multi-digit substring in 8, so this is a case of vacuous truth.

Specs

Standard loopholes apply, except that you are allowed to hardcode the output or store information related to the output in your program.

The numbers in the output can be in any order.

The numbers in the output are allowed to have duplicates.

You may use any separator, if you choose to print instead of output.

You are allowed to prefix and/or postfix output if you choose to print instead of output.

The separator and the prefix and the postfix may not contain any digits (U+0030 to U+0039).

Full list (58 items)

```<code>1
2
3
4
5
6
7
8
9
11
13
17
19
23
29
31
37
41
43
47
53
59
61
67
71
73
79
83
89
97
113
131
137
173
179
197
311
313
317
373
379
419
431
479
613
617
619
673
719
797
971
1373
3137
3797
6131
6173
6197
9719
</code>```

Reference

OEIS A131648 (incomplete list)

As always, please feel free to address in the comments anything I should clarify.

答:
05AB1E, <s>15</s> 13 bytes

Code:

```<code>4°GN§ŒD9›ÏpP–
</code>```

Explanation:

```<code>  G            # For N in range 1,
4°             #   10000
   N           # Push N
    §          # Convert that to string
     Œ         # Get all substrings
      D9›Ï     # Keep all substrings that are greater than 9
          p    # Check each of them if they are prime
           P   # Product
            –  # If 1, print N
</code>```

Uses the CP-1252 encoding. Try it online! (might take a few seconds).

Body:
05AB1E, <s>15</s> 13 bytes

Code:

4°GN§ŒD9›ÏpP–

Explanation:

  G            # For N in range 1,
4°             #   10000
   N           # Push N
    §          # Convert that to string
     Œ         # Get all substrings
      D9›Ï     # Keep all substrings that are greater than 9
          p    # Check each of them if they are prime
           P   # Product
            –  # If 1, print N

Uses the CP-1252 encoding. Try it online! (might take a few seconds).


答:
Befunge-98*, 19 bytes

```<code>&:39*\`'@\j;+,@;-.@
</code>```

Because the question said you'll receive a 1-26 or an A-Z I assumed this meant the number 26 or the character A-Z. Most interprets struggle with entering alt-codes, so it is easier to use & and enter values like 26 for 26 or 90 for 'Z', as opposed to ~.

Pseudo-code

```<code>int c = get stdin
push the value of 27
bool is_number =  27 > c
push the value of `@` (64)
if is_number == 1
   jump to adding 64 to c //putting it the ASCII range
   print as ASCII
   end
else
   jump to subtracting 64 from c //putting it in the numerical range
   print as number
   end
</code>```

Test it out (on Windows) here!

*This is technically Unefunge-98 because it only uses 1 dimension, but that name might be unfamiliar.

Body:
Befunge-98*, 19 bytes

&:39*\`'@\j;+,@;-.@

Because the question said you'll receive a 1-26 or an A-Z I assumed this meant the number 26 or the character A-Z. Most interprets struggle with entering alt-codes, so it is easier to use & and enter values like 26 for 26 or 90 for 'Z', as opposed to ~.

Pseudo-code

int c = get stdin
push the value of 27
bool is_number =  27 > c
push the value of `@` (64)
if is_number == 1
   jump to adding 64 to c //putting it the ASCII range
   print as ASCII
   end
else
   jump to subtracting 64 from c //putting it in the numerical range
   print as number
   end

Test it out (on Windows) here!

*This is technically Unefunge-98 because it only uses 1 dimension, but that name might be unfamiliar.


答:
PowerShell v2+, <s>107</s> 104 bytes

```<code>1..10+(11..1e4|?{($x=11..($i=$_)|?{"$i"-match$_}).count-eq($x|?{'1'*$_-match'^(?!(..+)\1+$)..'}).count})
</code>```

Warning: Kinda Slow

Loops from 11 to 1e4 (i.e., 10000) and pulls out numbers using the Where-Object selector (|?{...}). The clause is two components -- the first loops from 11 up to the current number and uses Where-Object to pull out those numbers that form a substring of the current number (via the -match regex operator). We store those substrings in $x. The second portion loops through $x and uses Where-Object to pull out all primes using the prime regex. We then take the .count of both and the check is actually whether those are -equal. For example, 971 will have $x = (71,97,971) and each of those are prime, so 3-eq3 is $TRUE and thus 971 will be selected.

That result is array-concatenated with a range 1..10. The resulting array is left on the pipeline and output is implicit, with a newline between elements by default.

Title: Print/Output all positive numbers in which every multi-digit substring in its decimal representation is also prime.

Body:
Task

Your task is to print or output all positive numbers in which every multi-digit substring in its decimal representation is also prime. If the number has at least 2 digits, this would imply that the number itself also needs to be prime.

Example

6197 is in the sequence because every multi-digit substring in 6197 is prime, namely: 61, 19, 97, 619, 197, 6197 (itself).

Note that 6 is not a prime but 6197 is still in the sequence because 6 is not a multi-digit substring of 6197.

8 is also in the sequence because every multi-digit substring in 8 is prime. There is no multi-digit substring in 8, so this is a case of vacuous truth.

Specs

Standard loopholes apply, except that you are allowed to hardcode the output or store information related to the output in your program.

The numbers in the output can be in any order.

The numbers in the output are allowed to have duplicates.

You may use any separator, if you choose to print instead of output.

You are allowed to prefix and/or postfix output if you choose to print instead of output.

The separator and the prefix and the postfix may not contain any digits (U+0030 to U+0039).

Full list (58 items)

```<code>1
2
3
4
5
6
7
8
9
11
13
17
19
23
29
31
37
41
43
47
53
59
61
67
71
73
79
83
89
97
113
131
137
173
179
197
311
313
317
373
379
419
431
479
613
617
619
673
719
797
971
1373
3137
3797
6131
6173
6197
9719
</code>```

Reference

OEIS A131648 (incomplete list)

As always, please feel free to address in the comments anything I should clarify.

Body:
PowerShell v2+, <s>107</s> 104 bytes

1..10+(11..1e4|?{($x=11..($i=$_)|?{"$i"-match$_}).count-eq($x|?{'1'*$_-match'^(?!(..+)\1+$)..'}).count})

Warning: Kinda Slow

Loops from 11 to 1e4 (i.e., 10000) and pulls out numbers using the Where-Object selector (|?{...}). The clause is two components -- the first loops from 11 up to the current number and uses Where-Object to pull out those numbers that form a substring of the current number (via the -match regex operator). We store those substrings in $x. The second portion loops through $x and uses Where-Object to pull out all primes using the prime regex. We then take the .count of both and the check is actually whether those are -equal. For example, 971 will have $x = (71,97,971) and each of those are prime, so 3-eq3 is $TRUE and thus 971 will be selected.

That result is array-concatenated with a range 1..10. The resulting array is left on the pipeline and output is implicit, with a newline between elements by default.


答:
Haskell, 83 bytes

```<code>q s="_":[s,s]
(f!w)h=take h$cycle$take w.drop(7-f).cycle<$>q"       |"++q"   |    "
</code>```

This defines a ternary infix function ! which returns a list of strings. Usage example:

```<code>*Main> putStrLn $ unlines $ (3!14) 7
______________
   |       |
   |       |
______________
       |
       |
______________
</code>```

How it works:

```<code>            q"       |"++q"   |    "  -- build a list of 6 strings
                                      --   1:     "_"
                                      --   2:     "       |"
                                      --   3:     "       |"
                                      --   4:     "_"
                                      --   5:     "   |    "
                                      --   6:     "   |    "
         <$>                          -- for each of the strings
     take w.drop(7-f).cycle           -- repeat infinitely, drop the first 7-f chars
                                      --    and take the next w chars
  cycle                               -- infinitely repeat the resulting list
take h                                -- and take the first h elements
</code>```

Body:
The purpose of this challenge is to produce an ASCII version of the cover of this great album by the rock band Pink Floyd.

The brick junctions are made of characters _ and |. Bricks have width 7 and height 2 characters, excluding junctions. So the basic unit, including the junctions, is:

```<code>_________
|       |
|       |
_________
</code>```

Each row of bricks is offset by half a brick width (4 chars) with respect to the previous row:

```<code>________________________________________
  |       |       |       |       |
  |       |       |       |       |
________________________________________
      |       |       |       |       |
      |       |       |       |       |
________________________________________
  |       |       |       |       |
  |       |       |       |       |
</code>```

The wall is parameterized as follows. All parameters are measured in chars including junctions:

Horizontal offset of first row, F. This is the distance between the left margin and the first vertical junction of the upmost row. (Remember also the half-brick relative offset between rows). Its possible values are 0, 1, ..., 7.

Total width, W. This includes junctions. Its value is a positive integer.

Total height, H. This includes junctions. Its value is a positive integer.

The top of the wall always coincides with the top of a row. The bottom may be ragged (if the total height is not a multiple of 3). For example, here's the output for 6, 44, 11:

```<code>____________________________________________
      |       |       |       |       |
      |       |       |       |       |
____________________________________________
  |       |       |       |       |       |
  |       |       |       |       |       |
____________________________________________
      |       |       |       |       |
      |       |       |       |       |
____________________________________________
  |       |       |       |       |       |
</code>```

and a visual explanation of parameters:

```<code>          F=6
         ......
     .   ____________________________________________
     .         |       |       |       |       |
     .         |       |       |       |       |
     .   ____________________________________________
     .     |       |       |       |       |       |
H=11 .     |       |       |       |       |       |
     .   ____________________________________________
     .         |       |       |       |       |
     .         |       |       |       |       |
     .   ____________________________________________
     .     |       |       |       |       |       |

         ............................................
                             W=44
</code>```

Additional rules

You may provide a program or a function.

Input format is flexible as usual. Output may be through STDOUT or an argument returned by a function. In this case it may be a string with newlines or an array of strings.

Trailing spaces or newlines are allowed.

Shortest code in bytes wins.

Test cases

Inputs are in the order given above, that is: horizontal offset of first row, total width, total height.

```<code>6, 44, 11:
____________________________________________
      |       |       |       |       |
      |       |       |       |       |
____________________________________________
  |       |       |       |       |       |
  |       |       |       |       |       |
____________________________________________
      |       |       |       |       |
      |       |       |       |       |
____________________________________________
  |       |       |       |       |       |

2, 20, 10:
____________________
  |       |       |
  |       |       |
____________________
      |       |
      |       |
____________________
  |       |       |
  |       |       |
____________________

1, 1, 1:
_

1, 2, 3:
__
 |
 |

3, 80, 21:
________________________________________________________________________________
   |       |       |       |       |       |       |       |       |       |
   |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
       |       |       |       |       |       |       |       |       |       |
       |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
   |       |       |       |       |       |       |       |       |       |
   |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
       |       |       |       |       |       |       |       |       |       |
       |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
   |       |       |       |       |       |       |       |       |       |
   |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
       |       |       |       |       |       |       |       |       |       |
       |       |       |       |       |       |       |       |       |       |
________________________________________________________________________________
   |       |       |       |       |       |       |       |       |       |
   |       |       |       |       |       |       |       |       |       |
</code>```

Body:
Haskell, 83 bytes

q s="_":[s,s]
(f!w)h=take h$cycle$take w.drop(7-f).cycle<$>q"       |"++q"   |    "

This defines a ternary infix function ! which returns a list of strings. Usage example:

*Main> putStrLn $ unlines $ (3!14) 7
______________
   |       |
   |       |
______________
       |
       |
______________

How it works:

            q"       |"++q"   |    "  -- build a list of 6 strings
                                      --   1:     "_"
                                      --   2:     "       |"
                                      --   3:     "       |"
                                      --   4:     "_"
                                      --   5:     "   |    "
                                      --   6:     "   |    "
         <$>                          -- for each of the strings
     take w.drop(7-f).cycle           -- repeat infinitely, drop the first 7-f chars
                                      --    and take the next w chars
  cycle                               -- infinitely repeat the resulting list
take h                                -- and take the first h elements


答:
R, 9 bytes

```<code>cat(1:10)
</code>```

cat prints, 1:10 creates the numbers 1 to 10.

Title: Print numbers from 1 to 10

Body:
This might be a very simple challenge, but I am surprised it hasn't been done on code-golf yet:

Print all Integers from 1 to 10 inclusive in ascending order to standard output.

Your output format can be whatever your language supports. This includes arbitrary separators (commas, semicolons, newlines, combinations of those, etc., but no digits), and prefixes and postfixes (like [...]). However, you may not output any other numbers than 1 through 10. Your program may not take any input. Standard loopholes are disallowed.

This is code-golf, so shortest answer in bytes wins!

Leaderboard

var QUESTION_ID=86075,OVERRIDE_USER=42570;function answersUrl(e){return"https://api.stackexchange.com/2.2/questions/"+QUESTION_ID+"/answers?page="+e+"&pagesize=100&order=desc&sort=creation&site=codegolf&filter="+ANSWER_FILTER}function commentUrl(e,s){return"https://api.stackexchange.com/2.2/answers/"+s.join(";")+"/comments?page="+e+"&pagesize=100&order=desc&sort=creation&site=codegolf&filter="+COMMENT_FILTER}function getAnswers(){jQuery.ajax({url:answersUrl(answer_page++),method:"get",dataType:"jsonp",crossDomain:!0,success:function(e){answers.push.apply(answers,e.items),answers_hash=[],answer_ids=[],e.items.forEach(function(e){e.comments=[];var s=+e.share_link.match(/\d+/);answer_ids.push(s),answers_hash[s]=e}),e.has_more||(more_answers=!1),comment_page=1,getComments()}})}function getComments(){jQuery.ajax({url:commentUrl(comment_page++,answer_ids),method:"get",dataType:"jsonp",crossDomain:!0,success:function(e){e.items.forEach(function(e){e.owner.user_id===OVERRIDE_USER&&answers_hash[e.post_id].comments.push(e)}),e.has_more?getComments():more_answers?getAnswers():process()}})}function getAuthorName(e){return e.owner.display_name}function process(){var e=[];answers.forEach(function(s){var r=s.body;s.comments.forEach(function(e){OVERRIDE_REG.test(e.body)&&(r="
"+e.body.replace(OVERRIDE_REG,"")+"
")});var a=r.match(SCORE_REG);a&&e.push({user:getAuthorName(s),size:+a[2],language:a[1],link:s.share_link})}),e.sort(function(e,s){var r=e.size,a=s.size;return r-a});var s={},r=1,a=null,n=1;e.forEach(function(e){e.size!=a&&(n=r),a=e.size,++r;var t=jQuery("#answer-template").html();t=t.replace("{{PLACE}}",n+".").replace("{{NAME}}",e.user).replace("{{LANGUAGE}}",e.language).replace("{{SIZE}}",e.size).replace("{{LINK}}",e.link),t=jQuery(t),jQuery("#answers").append(t);var o=e.language;/s.lang?1:e.lang<s.lang?-1:0});for(var c=0;c<t.length;++c){var i=jQuery("#language-template").html(),o=t[c];i=i.replace("{{LANGUAGE}}",o.lang).replace("{{NAME}}",o.user).replace("{{SIZE}}",o.size).replace("{{LINK}}",o.link),i=jQuery(i),jQuery("#languages").append(i)}}var ANSWER_FILTER="!t)IWYnsLAZle2tQ3KqrVveCRJfxcRLe",COMMENT_FILTER="!)Q2B_A2kjfAiU78X(md6BoYk",answers=[],answers_hash,answer_ids,answer_page=1,more_answers=!0,comment_page;getAnswers();var SCORE_REG=/<h\d>\s*([^\n,]*[^\s,]),.*?(\d+)(?=[^\n\d<>]*(?:<(?:s>[^\n<>]*<\/s>|[^\n<>]+>)[^\n\d<>]*)*<\/h\d>)/,OVERRIDE_REG=/^Override\s*header:\s*/i;```
<pre class="snippet-code-css lang-css prettyprint-override"><code>body{text-align:left!important}#answer-list,#language-list{padding:10px;width:290px;float:left}table thead{font-weight:700}table td{padding:5px}</code>```

 <link rel="stylesheet" type="text/css" href="//cdn.sstatic.net/codegolf/all.css?v=83c949450c8b">

Leaderboard

	Author	Language	Size

Winners by Language

Language	User	Score

{{PLACE}}	{{NAME}}	{{LANGUAGE}}	{{SIZE}}	Link

{{LANGUAGE}}	{{NAME}}	{{SIZE}}	Link

```

Body:
R, 9 bytes

cat(1:10)

cat prints, 1:10 creates the numbers 1 to 10.


答:
C#, <s>261</s> <s>249</s> 247 bytes

Saved 12 bytes thanks to Leaky Nun

```<code>()=>{Action<int>w=System.Console.WriteLine;int i=0,n,j,k,p,m,b;for(;++i<10001;){n=(i+"").Length;if(n<2)w(i);else{b=1;for(j=1;++j<=n;)for(k=0;k+j<=n;){p=int.Parse((i+"").Substring(k++,j));if(p%2<1)b=0;for(m=3;m<p;m+=2)if(p%m<1)b=0;}if(b>0)w(i);}}};
</code>```

This compiles to a Func<List<int>>.

The formatted version looks like:

```<code>() =>
{
    Action<int> w = System.Console.WriteLine;

    int i = 0, n, j, k, p, m, b;

    for (; ++i < 10001;)
    {
        n = (i + "").Length;

        if (n < 2)
            w(i);

        else
        {
            b = 1;
            for (j = 1; ++j <= n; )
                for (k = 0; k + j <= n; )
                {
                    p = int.Parse((i + "").Substring(k++, j));

                    if (p % 2 < 1)
                        b = 0;

                    for (m = 3; m < p; m += 2)
                        if (p % m < 1)
                            b = 0;
                }

            if (b > 0)
                w(i);
        }
    }
};
</code>```

Body:
C#, <s>261</s> <s>249</s> 247 bytes

Saved 12 bytes thanks to Leaky Nun

()=>{Action<int>w=System.Console.WriteLine;int i=0,n,j,k,p,m,b;for(;++i<10001;){n=(i+"").Length;if(n<2)w(i);else{b=1;for(j=1;++j<=n;)for(k=0;k+j<=n;){p=int.Parse((i+"").Substring(k++,j));if(p%2<1)b=0;for(m=3;m<p;m+=2)if(p%m<1)b=0;}if(b>0)w(i);}}};

This compiles to a Func<List<int>>.

The formatted version looks like:

() =>
{
    Action<int> w = System.Console.WriteLine;

    int i = 0, n, j, k, p, m, b;

    for (; ++i < 10001;)
    {
        n = (i + "").Length;

        if (n < 2)
            w(i);

        else
        {
            b = 1;
            for (j = 1; ++j <= n; )
                for (k = 0; k + j <= n; )
                {
                    p = int.Parse((i + "").Substring(k++, j));

                    if (p % 2 < 1)
                        b = 0;

                    for (m = 3; m < p; m += 2)
                        if (p % m < 1)
                            b = 0;
                }

            if (b > 0)
                w(i);
        }
    }
};


答:
R, 19 Bytes

```<code> ->n;sum(!n%%1:n)==2
</code>```

Starts with a right assign to n. i.e. precede the code with the desired n. then it merely checks primeness of n. Prints TRUE or FALSE implicitly

If you don't like right assign as an input method then for 24 bytes you get:

```<code>sum(!(n=scan())%%1:n)==2
or
n=scan();sum(!n%%1:n)==2
</code>```

Which assigns within the operator.

If you want explicit answer printing, then for 28 bytes:

```<code> p=function(n)sum(!n%%1:n)==2
</code>```

Title: Is this number a prime?

Body:
Believe it or not, we do not yet have a code golf challenge for a simple primality test. While it may not be the most interesting challenge, particularly for "usual" languages, it can be nontrivial in many languages.

Rosetta code features lists by language of idiomatic approaches to primality testing, one using the Miller-Rabin test specifically and another using trial division. However, "most idiomatic" often does not coincide with "shortest." In an effort to make Programming Puzzles and Code Golf the go-to site for code golf, this challenge seeks to compile a catalog of the shortest approach in every language, similar to "Hello, World!" and Golf you a quine for great good!.

Furthermore, the capability of implementing a primality test is part of our definition of programming language, so this challenge will also serve as a directory of proven programming languages.

Task

Write a full program that, given a strictly positive integer n as input, determines whether n is prime and prints a truthy or falsy value accordingly.

For the purpose of this challenge, an integer is prime if it has exactly two strictly positive divisors. Note that this excludes 1, who is its only strictly positive divisor.

Your algorithm must be deterministic (i.e., produce the correct output with probability 1) and should, in theory, work for arbitrarily large integers. In practice, you may assume that the input can be stored in your data type, as long as the program works for integers from 1 to 255.

Input

If your language is able to read from STDIN, accept command-line arguments or any other alternative form of user input, you can read the integer as its decimal representation, unary representation (using a character of your choice), byte array (big or little endian) or single byte (if this is your languages largest data type).

If (and only if) your language is unable to accept any kind of user input, you may hardcode the input in your program.

In this case, the hardcoded integer must be easily exchangeable. In particular, it may appear only in a single place in the entire program.

For scoring purposes, submit the program that corresponds to the input 1.

Output

Output has to be written to STDOUT or closest alternative.

If possible, output should consist solely of a truthy or falsy value (or a string representation thereof), optionally followed by a single newline.

The only exception to this rule is constant output of your language's interpreter that cannot be suppressed, such as a greeting, ANSI color codes or indentation.

Additional rules

This is not about finding the language with the shortest approach for prime testing, this is about finding the shortest approach in every language. Therefore, no answer will be marked as accepted.

Submissions in most languages will be scored in bytes in an appropriate preexisting encoding, usually (but not necessarily) UTF-8.

The language Piet, for example, will be scored in codels, which is the natural choice for this language.

Some languages, like Folders, are a bit tricky to score. If in doubt, please ask on Meta.

Unlike our usual rules, feel free to use a language (or language version) even if it's newer than this challenge. If anyone wants to abuse this by creating a language where the empty program performs a primality test, then congrats for paving the way for a very boring answer.

Note that there must be an interpreter so the submission can be tested. It is allowed (and even encouraged) to write this interpreter yourself for a previously unimplemented language.

If your language of choice is a trivial variant of another (potentially more popular) language which already has an answer (think BASIC or SQL dialects, Unix shells or trivial Brainfuck derivatives like Headsecks or Unary), consider adding a note to the existing answer that the same or a very similar solution is also the shortest in the other language.

Built-in functions for testing primality are allowed. This challenge is meant to catalog the shortest possible solution in each language, so if it's shorter to use a built-in in your language, go for it.

Unless they have been overruled earlier, all standard code-golf rules apply, including the http://meta.codegolf.stackexchange.com/q/1061.

As a side note, please don't downvote boring (but valid) answers in languages where there is not much to golf; these are still useful to this question as it tries to compile a catalog as complete as possible. However, do primarily upvote answers in languages where the author actually had to put effort into golfing the code.

Catalog

The Stack Snippet at the bottom of this post generates the catalog from the answers a) as a list of shortest solution per language and b) as an overall leaderboard.

To make sure that your answer shows up, please start your answer with a headline, using the following Markdown template:

```<code>## Language Name, N bytes
</code>```

where N is the size of your submission. If you improve your score, you can keep old scores in the headline, by striking them through. For instance:

```<code>## Ruby, <s>104</s> <s>101</s> 96 bytes
</code>```

If there you want to include multiple numbers in your header (e.g. because your score is the sum of two files or you want to list interpreter flag penalties separately), make sure that the actual score is the last number in the header:

```<code>## Perl, 43 + 2 (-p flag) = 45 bytes
</code>```

You can also make the language name a link which will then show up in the snippet:

```<code>## [><>](http://esolangs.org/wiki/Fish), 121 bytes
</code>```

 <link rel="stylesheet" type="text/css" href="//cdn.sstatic.net/codegolf/all.css?v=83c949450c8b">

Shortest Solution by Language

Language	User	Score

Leaderboard

	Author	Language	Size

{{PLACE}}	{{NAME}}	{{LANGUAGE}}	{{SIZE}}	Link

{{LANGUAGE}}	{{NAME}}	{{SIZE}}	Link

```

Body:
R, 19 Bytes

 ->n;sum(!n%%1:n)==2

Starts with a right assign to n. i.e. precede the code with the desired n. then it merely checks primeness of n. Prints TRUE or FALSE implicitly

If you don't like right assign as an input method then for 24 bytes you get:

sum(!(n=scan())%%1:n)==2
or
n=scan();sum(!n%%1:n)==2

Which assigns within the operator.

If you want explicit answer printing, then for 28 bytes:

 p=function(n)sum(!n%%1:n)==2


问:
Play a sound, any sound
Your program has to make the computer produce a sound, any sound.

Shortest code wins, not sooner than 10 days after the first valid answer. If there is a tie, the one submitted sooner, wins.

The program should run on a reasonable, not too uncommon personal computer.

Opening a pop-up, message box, etc. (for example, on a web page) does not count, as they might or might not produce a sound, depending on a lot of settings.

Just entering a wrong command or invalid character on a console and receiving a warning beep does not count, just as the compiler/interpreter/OS beeping on an error or crash does not count either. Your code must be a valid program.

答:
Ruby 8

```<code> puts"\a"
</code>```

Tested on Windows with Ruby 1.9.3.

Title: Play a sound, any sound

Body:
Ruby 8

 puts"\a"

Tested on Windows with Ruby 1.9.3.


答:
Jelly, 17 bytes

```<code>DẆṖÐfḌÆP€Ạ
³²RÇÐf
</code>```

My first Jelly answer! Saved 3 bytes thanks to @Leaky Nun!

Try it online

Explanation:

```<code>DẆṖÐfḌÆP€Ạ      The helper link, which checks if a given number satisfy the conditions.
DẆ              Convert the argument to a list of its digits and get all its substrings.
  ṖÐf           Remove all lists of length 1.
     ḌÆP€Ạ      Convert back each element to an integer and check if all of them are prime.

³²RÇÐf          Main link.
³²              Create a 100 and square it, which gives 10000.
  R             Create a list from 1 to it.
   ÇÐf          Filter out all the elements where the helper link gives false.
</code>```

Body:
Jelly, 17 bytes

DẆṖÐfḌÆP€Ạ
³²RÇÐf

My first Jelly answer! Saved 3 bytes thanks to @Leaky Nun!

Try it online

Explanation:

DẆṖÐfḌÆP€Ạ      The helper link, which checks if a given number satisfy the conditions.
DẆ              Convert the argument to a list of its digits and get all its substrings.
  ṖÐf           Remove all lists of length 1.
     ḌÆP€Ạ      Convert back each element to an integer and check if all of them are prime.

³²RÇÐf          Main link.
³²              Create a 100 and square it, which gives 10000.
  R             Create a list from 1 to it.
   ÇÐf          Filter out all the elements where the helper link gives false.


问:
Simulate a game of Craps
Craps is a fairly simple dice game often played in casinos. Even if you aren't a gambler (which I'm not), it's still a fairly interesting game. Here's the rules:

At the start of a game of Craps there's what is called the come-out round. The player rolls two d6s (six-sided die) and the two die rolls are added. If the result is 7 or 11, the person automatically wins (this is known as a natural). If the result is 2, 3 or 12 the person automatically loses (this is known as crapping out). Otherwise, the result is set as the point for the point round.

After this, the point round begins. During the point round, the player must continuously roll 2 d6s until the person rolls a 7 or his/her point from the previous round. If the person rolls a 7, they lose. If they roll their point, they win.

Challenge

Implement a simple program that simulates a game of craps. If the person rolls a natural or a crap-out during the come-out round, the program should output "Natural: " or "Crapping out: " followed by the die-roll and then exit. Otherwise, it should output "Point: " followed by the point. Then, during the point round, it should output every die-roll until a 7 or the point is reached. If the person wins, it should output "Pass"; if they lose it should output "Don't Pass".

Reference Implementation

Groovy, 277 bytes

```<code>def a={return Math.random()*6+1};int b=a()+a();(b<4||b==12)?{println"Crapping out: "+b}():{(b==7||b==11)?{println"Natural: "+b}():{println"Point: "+b;for(;;){int x=a()+a();println x;(x==7)?{println"Don't Pass";System.exit(0)}():{if(x==b){println"Pass";System.exit(0)}}()}}()}()
</code>```

Try it online.

Sample outputs

Natural: 7

Crapping out: 3

```<code>Point: 9
4
8
11
9
Pass
</code>```

and

```<code>Point: 5
3
7
Don't Pass
</code>```

This is code-golf, so shortest code wins.

(DISCLAIMER: This challenge is not intended to promote gambling in any way. Remember, the house always wins.)

答:
R, 197 bytes

```<code> r=sum(sample(6,2,T));if(r%%12<4)cat("Crap Out",r)else if(r%%4==3)cat("Natural",r)else{cat("Point",r);while(T){cat("",q<-sum(sample(6,2,T)));if(q==7){cat(" Don't");break};if(q>r)break};cat(" Pass")}
</code>```

Ungolfed

```<code>r=sum(sample(6,2,T))
if (r%%12<4)  {
    cat("Crap Out",r)
} else if (r%%4==3) {
    cat("Natural",r)
} else {
    cat("Point",r)
    while (T) {
        q = sum(sample(6,2,T))
        cat("",q)
        if (q==7) {
            cat(" Don't")
            break
        }
        if (q>r) break
    }
    cat(" Pass")
}
</code>```

Title: Simulate a game of Craps

Body:
R, 197 bytes

 r=sum(sample(6,2,T));if(r%%12<4)cat("Crap Out",r)else if(r%%4==3)cat("Natural",r)else{cat("Point",r);while(T){cat("",q<-sum(sample(6,2,T)));if(q==7){cat(" Don't");break};if(q>r)break};cat(" Pass")}

Ungolfed

r=sum(sample(6,2,T))
if (r%%12<4)  {
    cat("Crap Out",r)
} else if (r%%4==3) {
    cat("Natural",r)
} else {
    cat("Point",r)
    while (T) {
        q = sum(sample(6,2,T))
        cat("",q)
        if (q==7) {
            cat(" Don't")
            break
        }
        if (q>r) break
    }
    cat(" Pass")
}