Questions tagged [open-ended-function]
For challenges where an exact output is not required but some property must still be fulfilled.
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Turing-Complete Language Interpreter
A challenge I thought that would be very cool is to make an interpreter for a Turing-complete language of your choosing.
The rules are simple:
You may use any language to create this interpreter ...
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votes
3
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Convert to Chomsky normal form
Let a context-free language be specified by its production rules and start symbol, e.g.
S -> AbB | C
C -> b | c
B -> AA | AC
A -> a | ε
Here and in the ...
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Golf a number bigger than Loader's number
As a follow up to Shortest terminating program whose output size exceeds Graham's number and Golf a number bigger than TREE(3), I present a new challenge.
Loader's number is a very large number, ...
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As close to flat as possible
Write a program or function that fulfills the following
Scores less than 101 bytes under normal code-golf rules
Takes no input1 and always outputs a single integer.
Every integer is a possible output....
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168
answers
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Print all integers
Write a program or function which will provably print all integers exactly once given infinite time and memory.
Possible outputs could be:
...
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25
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Generate an arbitrary half of a string
Given a string \$ x \$, we say another string \$ y \$ is half of it, if both of the following properties are true:
\$ y \$ is a (not necessarily continuous) subsequence of \$ x \$ - there exists a ...
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Create an array with repeated numbers
Challenge
Your task in this question is to write a program or a named function which takes a positive integer n (greater than 0) as input via STDIN, ARGV or ...
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12
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Infinite ordinals from a well-ordering
Your task is to write a short program that represents a large (infinite) ordinal, using a well-ordering of the set of positive integers. Your program will take two different positive integers and ...
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Output a random unary string
Your task is simple: output the letter x a random number of times. Every possible length of xs must have a non-zero probability ...
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84
answers
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Print some JSON
This challenge is straightforward, but hopefully, there are plenty of avenues you can approach it:
You need to print/return a valid JSON object of at least 15 characters, not counting unessential ...
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Infinitely many ℕ
Background:
A sequence of infinite naturals is a sequence that contains every natural number infinitely many times.
To clarify, every number must be printed multiple times!
The Challenge:
Output a ...
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BigNum Bakeoff Reboot
Some of you may be familiar with the BigNum Bakeoff, which ended up quite interestingly. The goal can more or less be summarized as writing a C program who's output would be the largest, under some ...
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Output a 1-2-3 sequence
For the purposes of this challenge, a 1-2-3 sequence is an infinite sequence of increasing positive integers such that for any positive integer \$n\$, exactly one of \$n, 2n,\$ and \$3n\$ appears in ...
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votes
4
answers
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Output a 1-2-3-5-7... sequence
Follow-up of my previous challenge, inspired by @emanresu A's question, and proven possible by @att (Mathematica solution linked)
For the purposes of this challenge, a 1-2-3-5-7... sequence is an ...
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12
votes
7
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Mapping Passing Through Point
(Inspired by this challenge.)
Given six real values in three pairs: \$(x_1, x_2), (y_1, y_2),\$ and \$(x_0, y_0)\$, where \$x_1 < x_0 < x_2\$ and \$y_1 < y_0 < y_2\$, create a function ...
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votes
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Transform characters of your choice into "Hello, world!"
Write a program or function that takes a character as input and outputs a character. Also, choose a list of 13 distinct ASCII printable characters (32-126). When a character from this list is passed ...
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Egyptian fraction representations of 1
An Egyptian fraction is a representation of a rational number using the sum of distinct unit fractions (a unit fraction is of the form \$ \frac 1 x \$ where \$ x \$ is a positive integer).
For all[1] ...
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Three other numbers
Given three distinct numbers from \$1\$ to \$7\$, output three other distinct numbers from \$1\$ to \$7\$, that is having no numbers in common with the original numbers. Your code must produce a ...
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7
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Horsey sightseeing
A knight's tour is a sequence of moves of a knight on a chessboard such that the knight visits every square only once. For those who are not aware of how knights in chess work, knights are capable of ...
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votes
9
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Output an infinitely proportional sequence
In this challenge, an infinitely proportional sequence is defined as a infinite sequence of positive integers such that:
All positive integers are contained infinitely many times within the sequence.
...
- 1,368
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votes
22
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Be big more often
Related
You are a manager at a large number factory. You want to show everyone your business is doing well, by showing randomly chosen samples. Unfortunately, your business is not doing that well. But ...
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Encode the input to exclude a given character (part 1)
Your task is to write 2 functions/programs. They may share code.
The first function must, given a string and a character, output a new string that does not contain that character.
The second function ...
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votes
0
answers
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Give the best Chaitin incompleteness bound
This was originally a pure mathematics question, but I think I've got the best chance for an answer here.
The Challenge
For concreteness, consider Peano Arithmetic (PA). For some language L of your ...
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votes
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Make a super fair number
An even distribution number is a number such that if you select any of it's digits at random the probability of it being any particular value (e.g. 0 or ...
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15
votes
4
answers
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Output a Steiner quadruple system
A Steiner quadruple system \$SQS(n)\$ is a collection of subsets (blocks) of size 4 of a set \$S\$ of size \$n\$ such that every subset of \$S\$ of size 3 is in exactly one block. It is easy to show ...
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votes
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Convert numbers to dice patterns
The way points are assigned on a dice follows a regular pattern, the center dot is present if and only if the number is odd. To represent the even numbers, pairs of dots on opposite sides of the ...
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votes
8
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Generate all linked chains
A followup to this challenge by Jeremy Collprav, inspired by DLosc solving this in Regenerate. Some sections copied from the linked challenge.
Linking chains
We define a chain to be a string ...
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answers
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Give the fool's Fibonacci sequence
Recently I asked for tips on improving some code-golf of mine. The code was supposed to output every third value of the Fibonacci sequence starting with 2:
...
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votes
5
answers
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Prefix code generator
In this challenge, we consider an encoding from positive integers (up to a limit) to binary sequences. Some examples:
...
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13
votes
14
answers
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Generate a permutation from the high-water marks
Given a permutation, we can define its high-water marks as the indices in which its cumulative maximum increases, or, equivalently, indices with values bigger than all previous values.
For example, ...
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Enumerate all pure sets
In set theory, a set is an unordered group of unique elements. A pure set is either the empty set \$\{\}\$ or a set containing only pure sets, like \$\{\{\},\{\{\}\}\}\$.
Your challenge is to write a ...
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Adjacent Items Sorting
Given a list, L, of sets of numbers like this:
[[1], [0,2,3], [3,1], [1,2,3]]
Output a single list of numbers such that 2 ...
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votes
5
answers
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Sudoku as a SAT problem
Background
An interesting way to solve a Sudoku puzzle is to represent it as a Boolean satisfiability problem, and then feed it to a SAT solver.
A Boolean Satisfiability Problem (abbreviated as SAT ...
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Output every sublist ... eventually
You will be given as input an infinite stream of positive integers.
Your task is to write a program which outputs an infinite sequence of lists with two requirements:
All lists in the output are ...
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Enumerate the rationals
The cardinality of the set \$\mathbb Q\$ of rational numbers is known to be exactly the same as that of the set \$\mathbb Z\$ of integers. This means that it is possible to construct a bijection ...
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Don't repeat yourself
In this challenge you will be tasked with implementing a sequence of natural numbers such that:
Each number appears a natural number of times
No two numbers appear the same number of times
No two ...
- 6,261
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votes
1
answer
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Busy beaver in a coin
\$BB\$ is the busy beaver function, an uncomputable function.
Write a program which when given an integer \$n\$ as input, will output \$BB(n)\$, with at least \$\frac 2 3\$ probability. You can do ...
CommunityBot
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Add two real numbers ... probably
The problem statement here is pretty simple, take two real numbers on the range [0,1) as input and output their sum, with probability 1.
The catch here is that there are a lot of real numbers. There ...
- 36.2k
8
votes
3
answers
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Injectively saturate bit strings
It can be easily proven using Hall's marriage theorem that given fixed \$n\$ and \$k<n/2\$, there is an injective (one-to-one) function from all \$n\$-bit strings with \$k\$ ones to \$n\$-bit ...
- 6,261
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votes
6
answers
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Generate number from given range
Your function must accept three numbers in any order:
A signed real number (or ±Infinity) - The number (N) for which you have ...
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votes
6
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Approximate a root of an odd degree polynomial
Every odd degree polynomial has at least one real root. However this root does not have to be a rational number so your task is to output a sequence of rational numbers that approximates it.
Rules
...
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Code Golf: Mix the nuts so that none of the same kind are touching
Input:
Input is a randomized array of nuts (in your language), the possible nuts follow. Your program must have a way of representing each kind of nut, such as an integer code. Program must be able ...
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Split some points
proposed by @Adám in chat
Given an even number of finite points return a line \$y=mx+b\$ that evenly splits the points on both sides.
Specs
Take a list of distinct points \$(x,y)\$ (or a list of x-...
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4
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Number-only switch
Write a function that takes an ASCII-printable-only (all charcodes ∈ [32..126]) string input x and provides an ASCII-printable-only output string ...
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Surjection from one string to two strings
This is the inverse of negative seven's question.
Write a program or function which, given any single, possibly-empty string of printable ASCII (codes \$[32,126]\$) outputs or returns two strings of ...
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Give me odd, even, square, cube, prime and composite 3-digit numbers
Given a string which is guaranteed to be either odd, even, square, ...
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votes
2
answers
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Don't output the file 2
Last time you were required to write program that output a file, such that no byte is same as original file. The request meant to let everyone carry part of information, but it ends up that everyone ...
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votes
5
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Generate number set with conditions using n numbers
Generate \$T=\{T_1,...,T_x\}\$, the minimum number of \$k\$-length subsets of \$\{1,...,n\}\$ such that every \$v\$-length subset of \$\{1,...,n\}\$ is a subset of some set in \$T\$
Here, \$n > k &...
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Walk Across a Keyboard
Given a word (or any sequence of letters) as input, you must interpolate between each letter such that each adjacent pair of letters in the result is also adjacent on a QWERTY keyboard, as if you ...
- 10.5k
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votes
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answer
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Show a balanced binary tree
Given an integer \$n > 1\$, output a balanced binary tree with \$n\$ leaf nodes.
The tree should be constructed out of (space), ...
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