New Sandboxed Posts
Should I index like this or like that? code-golf integer decision-problem
Challenge
Let's take a 0-indexed array of length \$l\$. You can index into it with \$i\$, where \$-l\le i<l\$, and the returned element is the element in position \$[i<0]\times l+i\$ (\$[\dots]\$ is the Iverson bracket).
...
Polite Near-Sighted Drunk Bot on a Minefield
As the title may suggest, this problem is semi-inspired by the Polite Near-Sighted Drunk Bot by @N.P.
Our poor bot is placed on a cartesian grid at the origin, and after each minute, it moves 1 unit in one of four directions (Up, Down, Left, Right)....
P Pr Pre Pref Prefi Prefix Prefixe Prefixes
code-golflistarray
Given some finite list, return a list of all its prefixes, including an empty list, in ascending order of their length.
(Basically implementing the Haskell function inits.)
Details
The input list contains numbers (or another ty...
Chain Classification
answer-chaining
related
Objective: Write a program (whose index in the chain of answers is \$n\$) which, when given any program with index \$i\$ (\$ 1 \le i \le n\$), outputs \$i\$.
(The program may do anything else given any other string input, including but not limited ...
Meta:
I'm reposting this in the sandbox on behalf of behalf of @RushabhMehta.
It was in main for a couple of days but we decided that it needs more time in the sandbox to resolve some issues.
Today's challenge will involve some interesting knot theory, and involve you calculating one of the mo...
Reverse the Flags
code-golf kolmogorov-complexity
Challenge
Given a flag emoji as input, output its reversed emoji.
What does this mean? Well, if you take the UK flag emoji, 🇬🇧, and run it through the python program:
print(''.join(reversed("🇬🇧")))
Try it online!
Then the output will b...
Golf me some Golf
code-golf game
Write a program to play Golf solitaire!
(I'm somewhat surprised that I haven't seen this pun yet.)
How to play
Golf uses a standard 52 card deck. Play begins with 7 stacks of 5 cards each, one card forming the foundation, and the remaining 16 cards forming the...
Most distinct Turing-complete character subsets
(Inspired by Fewest (distinct) characters for Turing Completeness)
code-challenge restricted-source
Challenge:
In any language you choose, find the greatest number of distinct and disjoint subsets of characters allowed in that language (i.e. no ...
Expand and Contract
code-golf number decimal
Take a positive integer \$k\$ as input. Start with \$n := 1\$ and repeatedly increase \$n\$ by the largest integer power of ten \$i\$ such that \$i \le n\$ and \$i + n \le k\$.
Repeat until \$n = k\$, returning all intermediate values of \$n\$.
Dur...
Make a reversible formula
For the purposes of this question:
a basic formula \$ y = f(x) \$ takes one of the following forms:
$$ x \\ g(x) + c \\ c + g(x) \\ g(x) - c \\ c - g(x) \\ g(x) c \\ c g(x) \\ \frac {g(x)} c \\ \frac c {g(x)} $$
where \$ g(x) \$ is a basic formula;
a reversible f...
alphabeTree
Challenge
When looking at a list of words, sometimes it seems like a lot of redundancy is present. Consider the following list of words:
balderdash
ballet
balloonfish
balloonist
ballot
brooding
broom
All of the words start with b, and the first 5 start with bal. If we just look a...
4B/5B Encoding
Tags: code-golf, encode, kolmogorov-complexity, string
To transmit data in binary there's a technique called NRZI where a transition from +V to -V or vice-versa encodes a 1 and the absence of such a transition a 0.
In case there are a lot of 1 s this is a good method because t...
Game of Circles king-of-the-hill
This is a hidden-identity game with Detectives and Robbers. You will write either a Detective bot or a Robber bot. All Robbers know the identity of all other Robbers. Each turn, a bot must either:
Draw a private circle:
The actual circle drawn is public in...
Mingle and Select
The programming language INTERCAL has two operators, "mingle" or "interleave" (represented by $), and "select" (represented by ~).
Mingle takes two 16-bit values and produces a 32-bit value by taking single bits alternately from its left and right operands, and concatenating t...
Fill up to duplicate ranges
Let \$L\$ be a list of positive integers with no particular ordering, and which can contain duplicates. Write a program or function which outputs a list of positive integers \$M\$ (whose ordering is unimportant) such that the union of \$L\$ and \$M\$ results in a list...
Numbers Addition
Challenge
Given a list of numbers K and a desired result N your task is to output the expression which can be used to get N using only plus operator + and minus operator -
Example:
[3,7,9,3,-5,7,0,-5], 11 => 3 + 7 + 9 - 3 - -5 - 5 + 0 + -5
Rules
Only one operator can be us...
Primality testing expression code-golf restriced-source decision-problem
Your goal is to determine whether a given number n is prime in the fewest bytes. But, your code must be a single Python 2 expression consisting of only
operators
the input variable n
integer constants
parentheses
No lo...
Bidirectional Reverse Quine
quine code-golf
Create a program that outputs its own source code in reverse order. This reversed quine should also be a program with the same properties. More succinctly, abc outputs cba and vice-versa.
Rules
No palindromes. There are already palindrome quine c...
A function to traverse an array and re-generate the same array
We take an array, then write a function that will traverse the array and generate the array in a format given in the example below.
For example, given the array:
Array
(
[0] => Array
( [name] => Tom
[age] => 32
[k...
Robot Economy
king-of-the-hill
In this KoTH, your bot will try to get rich. There are 3 ways to get money: Farming, Mining, and Fishing. As the bots collect items, they must sell these items to other bots. They can also upgrade tools. At the end of the time period, whichever bot has the most to...
Make the biggest and smallest numbers
Inspired by this post over on Puzzling. Spoilers for that puzzle are below.
Given three positive integers as input, (x, y, z), construct the inclusive range [x, y], concatenate that together, then remove z not-necessarily-consecutive digits to produce the l...
Compare version numbers
Input two version numbers (decimal numbers joined by dots in string format), compare them, and, output 3 distinct values for the result.
I cannot find a duplicate, if some one find it, please point it out.
Details will come up later if no duplicate found.
Define X as non-empty non-self-contain array of X and "1". Split an X into smallest amount of continuous parts Y, length of each of Y don't exceed n, so that each X is either part of a Y, or exactly some Ys. It's fine if output only express which part has how many 1's.
Samples:
[1,[1,1,1]],3 =>...
Work out Naismith's Rule code-golfnumber
Naismith's rule helps to work out the length of time needed for a walk or hike, given the distance and ascent.
Given a non-empty list of the altitude at points evenly spaced along a path and the total distance of that path in metres, you should calculate...
Edit distance for sparse strings
The input to this challenge will be two strings of length one million each. Each string contains only zeros and ones. However each string will contain at most 100 ones and so will be represented by a sorted list of integers. The integers will indicate where the ...
Advanced Transposition
code-golf array-manipulation
Inspired by the obscure 3rd optional argument of Mathematica's Flatten function
Introduction
Matrix transposition involves swapping the two indices in a rectangular 2d matrix.
For example,
$$ \begin{bmatrix}
1 & 2 & 3 & 4\\
5 & 6 & 7 & 8\\
9 
"Winner Winner Chicken Dinner"
king-of-the-hillgamegrid
In PUBG, 100 people fight in a large virtual arena. We, on the other hand, have neither 100 people, nor time to make such large virtual arena. So, We get our codes ready, and let them fight!
== IN PROGRESS, ADVICE NEEDED ==
Sixty percent of the time, it works every time
code-golf random kolmogorov-complexity
Your submission is a series of characters, that when rearranged in all possible permutations, should output Sex Panther* (in any case combination, so sex panther or SEx PaNTHer are valid) 60% or more of the ti...
Codegolf Rainbow : Fun with Integer-Arrays
code-golfinteger
Introduction:
(Source: Wikipedia)
When we look at a rainbow it will always have the colors from top to bottom:
Red; orange; yellow; green; blue; indigo; violet
If we look at these individual rings, the red ring is of course bigger t...