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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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
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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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9
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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 ...
- 96.5k
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votes
3
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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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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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5
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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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9
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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:
...
- 96.5k
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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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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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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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5
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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 ...
- 96.5k
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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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6
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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
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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votes
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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 ...
- 3,707
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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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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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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 ...
- 96.5k
8
votes
4
answers
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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 ...
- 20.5k
5
votes
2
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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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19
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10
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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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4
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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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votes
9
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Incomparable partitions
A partition of a list \$A\$ is a way of splitting \$A\$ up into smaller parts, concretely it is list of lists that when concatenated gives back \$A\$.
For example ...
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votes
11
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Create a nibble shorthand
I recently stumbled across this image on wikimedia commons. It's a little bit of an information overload at first, but after examining it a bit it shows an interesting number system for writing ...
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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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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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24
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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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votes
0
answers
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Bijective Function (mapping integer to arbitrarily large integer tuple) [duplicate]
Find a bijective function which maps integers to arbitrarily large tuples of integers. Given the input \$n\$, output the tuple it matches to.
Edit: The empty tuple is included in the mapping.
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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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Give f and g that sometimes commute
Let \$Z\$ be either the integers, the positive integers, or the non-zero integers; pick whatever's convenient. Give two functions \$f\$ and \$g\$, each \$Z \to Z\$, such that:
\$f(g(a)) = g(f(a))\$, ...
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Average-ignorant sets of integers
Recently a friend of mine posed the following:
What subset of the integers satisfies the condition if distinct a and b are in the subset, their average is not in the subset? I know the set of non-0 ...
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votes
3
answers
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Sniff out biased random permutations
The brilliant engineers at <enter company you love to hate> have struck again. This time they've "revolutionised" the generation of random permutations. "Every great invention is ...
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9
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Is it irrational?
Your task is to make a program that decides if a real number between 0 and 1 is irrational or not. As stated, this is obviously impossible, so instead we will use the following definition:
...
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15
votes
3
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What was my Wordle play?
Task
Given a winning Wordle play results (clues), the target ("secret") word and a list of words, output a possible sequence of words leading to such results.
The words in the list will be ...
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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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12
votes
8
answers
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All sequences as substrings
Make a program that outputs a sequence of integers so that every finite sequence of positive integers is a substring (continuous subsequence) of the output.
For example, the following sequence ...
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votes
4
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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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Don't output the file
This rar file, when decompressed, gives a 65024-byte exe file. Requiring you to output the contents of that file would be ...
- 20.5k
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votes
4
answers
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Probability breaking sequences
If we have a finite list of elements we can determine the probability of any one element being drawn at random as the number of times it occurs divided by the total number of elements in the list.
For ...
- 96.5k
10
votes
8
answers
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Biggest katlani noun dictionary in 400 bytes
Katlani is a constructed language being designed in chat. In this challenge, your goal is to print the largest dictionary of katlani nouns possible in 400 bytes or less.
Task
In 400 bytes or less, ...
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votes
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Compress and decompress
Your task is to make a bidirectional compressor. It takes a list of bytes as input and returns a list of bytes as output. It has the property than whenever it is iterated twice it returns the original ...
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votes
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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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7
votes
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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 ...
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votes
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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 ...
- 96.5k
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votes
8
answers
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Make every fixed list
We are to define the idea of a fixed list as follows:
A fixed list is a list of fixed lists.
This definition is recursive so it's useful to look at some examples.
The empty list ...
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Generate a regular graph
Inspired by this Mathematica.SE post
Given two positive integers \$n, k\$ with \$n > k \ge 1\$, output a binary \$n\times n\$ matrix such that every row and column contains exactly \$k\$ 1s, and ...
- 49.4k
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15
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Encode integers with some others
Input a non-empty array of positive (greater than 0) integers. Output another non-empty array of positive integers which encode the input array. Output array does not use any numbers used in the input ...
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Kolmogorov-simple numbers
If you visit Code Golf often, you may have heard of Kolmogorov complexity. It's usually defined as the amount of bytes required to express some string in a programming language.
Here the Kolmogorov-...
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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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votes
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Bijection between \$ \mathbb N \$ and at-most-\$n\$-ary trees
Background
Related: a golflang theory I posted in TNB a while ago
At-most-\$n\$-ary trees are rooted trees where each internal node has between 1 and \$n\$ children (inclusive). Two trees are ...
- 73.8k