The Post's Correspondence Problem (PCP) gives you a list of pairs of strings, P_1 ... P_n. Your task is to find a k, and some sequence of k indices such that fst(P_i1) ... fst(P_ik) = snd(P_i1) ... snd(P_ik)
We're trying to find some sequence of the pairs where the word we build from the first p...
![Wait, forgot to escape a space. Wheeeeee[taptaptap]eeeeee.](http://imgs.xkcd.com/comics/regular_expressions.png "Wait, forgot to escape a space. Wheeeeee[taptaptap]eeeeee.")
Stackylogic is a logic-based programming language I made up that take in 0's and 1's for input and outputs a single 0 or 1 upon completion.
A Stackylogic program consists of lines that can only contain the three characters 01? as well as exactly one < at the end of one of the lines. Lines may no...
Create the shortest function that finds the factorial of a natural number.
The factorial is found by multiplying a number by each of the numbers that lead up to it.
5! = 5 * 4 * 3 * 2 * 1 = 120
Requirements:
Does not use any built-in libraries that can calculate the factorial (this includes...
Brainfuck because its fun. Its easy to learn (only 8 commands) and its Turing complete, so its very flexible.
On Stackoverflow, if you click on an invalid link, you will be redirected to a 404 page with this polyglot:
# define v putchar
# define print(x) main(){v(4+v(v(52)-4));return 0;}/*
#>+++++++4+[>++++++<-]>++++.----.++++.*/
print(202*2);exit();
#define/*>.@*/exit()
(Originally written by Mark ...
For this golf, you will need to use more than one language.
The task
A Rube Goldberg machine is a contraption that takes an enormous number of complicated steps in order to execute a very simple task. The goal of this golf is to output Rube Goldberg... but not directly.
The machine
Your "mach...
Definition
Define the nth term of the CRAU sequence as follows.
Begin with the singleton array A = [n].
Do the following n times:
For each integer k in A, replace the entry k with k natural numbers, counting from 1 to k.
Compute the sum of all integers in A.
For example, if n = 3, we start ...
Challenge:
In your preferred programming language, you must parse a String into a real number (int or float). The String will only contain number characters (0, 1, 2, 3, 4, 5, 6, 7, 8, 9) and may contain a . to create a floating point. However, you may not use any pre-existing parsing functions ...
In this popular (and essential) computer science book, An Introduction to Formal Languages and Automata by Peter Linz, the following formal language is frequently stated.
mainly because this language can not be processed with finite-state automatons.
This expression mean "Language "L" consists...
