Find the maximum number of coprimes in a set
Inspired by a recent question on Math.stackexchange.com, which I can't find anymore.
The challenge
Exactly what it says on the tin. You are given a set of integers and you have to create a program (according to the default definitions on meta) that ...
Stolen from @Downgoat with permission
The point of this challenge is to (not) settle the debate on the pronunciation of "gif".
"
The pronunciation of gif is debated and while it's supposed to be (and should be) pronounced jif, it's still commonly disputed.
In this challenge you will be giv...
Beat the turing test king-of-the-hill
Both you and your bot have to connect to a speed dating chatroom (details below) where you will either be paired up with another bot, or with another human. You get 30 seconds to converse with your partner before you are disconnected, and are presented with ...
A dog on a chain
I'm looking out of my attic window into my neighbor's yard. They have a dog chained to a post in the center of the yard. The dog runs around the yard but is always on the end of its chain, so it ends up leaving a track in the dirt. Normally this track would be perfectly circul...
Primitive Repetition code-golf primes
A repunit in any base B is a number consisting solely of 1s in that base.
Your task is to figure out if a repunit consisting of N in base B is a prime number.
Rules
N >= 2
B >= 1
N and B may be taken in any order and in any reasonable method.
Output a co...
This is a comparison of regular expression engines.
== Libraries ==
== Languages ==
== Language features ==
NOTE: An application using a library for regular expression support does not necessarily offer the full set of features of the library, e.g. GNU grep which uses PCRE does not offer lookahead support, though PCRE does.
=== Part 1 ===
=== Part 2 ===
== API features ==
== See also ==
Regular expression § Implementations and running times
== References ==
== External links ==
Regular Expression Flavor Comparison — Detailed comparison of the most popular regular expressio...
Seems that .NET does not have recursion like PCRE, but does have balancing groups and variable length look-behinds, which PCRE doesn't have. (I don't really know what any of those things mean.) I guess both have pros and cons.
Luckily Dyalog APL has both PCRE and .NET regex built in. :-)
Aligned Subsequences
Given a string s and an integer n, generate all contiguous subsequences of length n from the start and align them. For example, given the string s = "abcdefg" and n = 4,
abcd
bcde
cdef
defg
Rules
Trailing whitespace is allowed.
n < len(s)
This is code-golf.
A re...
@Phoenix OK. Anyway, that is very far from my job in Dyalog. John takes care of things like that. He's made Dyalog APL GUI apps run on his smartwatch and TV.
@DestructibleLemon Yes, you did. I tend to miss or forget about pings in TNB though unless it's something I can attend to immediately. For all things TIO, it' better to ping me in talk.tryitonline.net
@Phoenix Just tried it in Dyalog APL, which does have op_Addtion, but it rejects the addition of a string to an object (a DateTime). However, that may be because + is not used for string concatenation in APL.
Objective
Undo a pig-latin string.
Instructions
Write a function that takes one argument, a single word in the form of a string. If that word is in pig-latin, the function must output (i.e. return or print it) the pig-latin undone word. If it isn't pig-latin, output the word as-is.
Pig-latin ...
Preface
This question is specifically targeting Java answers. I have little to no knowledge of any other program languages, though I expect that the questions I raise below will apply to other statically-typed languages as well. This question was "inspired" by this PPCG answer.
Java Lambdas
(s...
For the mod election questionnaire, I asked about a hypothetical situation:
A new-ish user posts a well-posed challenge that quickly gets many
answers. An hour later, they edit in a restriction that invalidates
most of the existing answers. An experienced user whose answer was
invalidat...
@HelkaHomba The deals are the same throughout the entire sale. Sometimes stuff goes on sale partway through, but that's not very common. Flash sales and daily sales aren't a thing anymore because of refund scamming.
One option would be that you know where your piece lands when you play it, but nothing else. The only way to tell where an opponent has played is to play on top of them, at which point you can determine how many pieces the opponent has played in that column since the last time you played in that column.