Questions tagged [code-golf]
Code-golf is a competition to solve a particular problem in the fewest bytes of source code.
9,556
questions
9
votes
11answers
135 views
Make a Rectangle from a Triangle
You can depict a triangular number, T(N), by writing one 1 on a line, then two 2's on the line below, then three 3's on the line below that, and so on until N N's. You end up with a triangle of T(N) ...
10
votes
7answers
162 views
Minimal Rotate-Right-Double numbers in base n
Task
For a given base \$n \ge 3\$, find the smallest positive integer \$m\$, when written in base \$n\$ and rotated right once, equals \$2m\$. The base-\$n\$ representation of \$m\$ cannot have ...
7
votes
5answers
1k views
Is this a rectangle?
The challenge:
Given four coordinates, each in x y form, your job is to find out whether or not the given coordinates form a rectangle, and output a truthy/falsey.
Rules:
For the sake of simplicity,...
15
votes
32answers
1k views
Triangular code, triangular output
For this challenge, submissions should be a program or function shaped like a right triangle, which produces a right triangle of the same size.
What is a right triangle?
For this challenge, a right ...
18
votes
21answers
1k views
Convert to and from Base 94
The challenge
Make 2 programs which convert decimal to and from base 94, or a bidirectional program.
Base 94?
Base 94 is like any other base, but instead of 0 to 9 and letters, it uses ASCII ...
23
votes
9answers
599 views
Maintain diagonal symmetry when placing N items on a square grid
Write a program that takes in two non-negative integers S and N in that order. S represents the side length of a square grid of . characters. N represents the ...
3
votes
0answers
76 views
Decode Arabic to Arabic Presentation Form
Objective
Given an Arabic string consisting of ISO/IEC 8859-6 Arabic letters (U+0621–063A, 0640–064A), decode it to Arabic Presentation Forms-B (U+FE70–FEFF).
Behavior of Arabic letters
ISO/IEC ...
28
votes
17answers
2k views
Check membership of an infinite list
As input you will receive
An integer \$a\$
A list of integers that is infinite and strictly-monotonic1.
Your program should check in finite time if \$a\$ appears the list.
You should output one of ...
12
votes
3answers
635 views
Code golf edit distance 2
The edit distance between two strings is the minimum number of single character insertions, deletions and substitutions needed to transform one string into the other.
This task is simply to write ...
2
votes
9answers
199 views
Does base n have any Rotate-Left-Double numbers?
Task
A Rotate-Left-Double number in base \$n\$ is a number \$m\$, when its base-\$n\$ digits are rotated left once, equals \$2m\$. The base-\$n\$ representation of \$m\$ cannot have leading zeros.
...
12
votes
5answers
688 views
Boil eggs using hourglasses
These are the classical puzzles:
You need to boil eggs for exactly 9 minutes, or else the visiting Duchess will complain, and you will lose your job as head chef.
But you have only 2 ...
9
votes
3answers
334 views
Multiplayer Rock-Paper-Scissors
Objective
Given a nonempty multiset of Rock, Paper, and Scissors, output the winning figure ...
14
votes
19answers
1k views
Mirror and reverse text
Inspired by I reverse the source code, ...
Your task, if you wish to accept it, is to reverse text and mirror select characters. Yes, yes, I know. Very surprising.
Input
A string, ...
26
votes
34answers
5k views
How happy is this emoticon?
In this challenge, submissions will be programs or function which, when given an emoticon such as :-), :(, or ...
24
votes
12answers
5k views
Is this a legal date? - April Fools' edition
Task
A date can be compactly represented in a 6-character string in the format ddmmyy where the first two characters (dd) ...
18
votes
14answers
2k views
Let's decompress a bit
Given a compressed string \$s\$ made of printable ASCII characters (32 to 126), your task is to print or return the original text by applying this simple decompression algorithm:
Start with \$k=0\$
...
15
votes
14answers
1k views
Generating generating expressions for sequences
(yes, "generating generating" in the title is correct :) )
Context
In middle (?) school we are taught about sequences and, in particular, we are taught about linear sequences where the ...
19
votes
13answers
1k views
Convert Planck unit to SI metric
Objective
Given a dimension of an SI unit, convert the Lorentz-Heaviside version of a Planck unit \$1\$ into SI metric.
What is a Planck unit?
Planck units are a set of units of measurement. It ...
35
votes
13answers
6k views
God is real . . . unless declared integer
This challenge is inspired by Fortran's idiosyncratic implicit typing rules. Your task will be to determine the data type of the object GOD according to the ...
12
votes
14answers
2k views
Pseudo-deterministic number generator
Task
Write a function/full program that will be able to produce two different sequences of integers in [0, ..., 9]. You will take an input ...
26
votes
7answers
5k views
Draw an ASCII oak tree (or a woman with curly hair?)
Task
Your task is to draw these beautiful oak trees:
...
23
votes
18answers
2k views
Cook me a character meal
Chef Avillez is about to cook us some really nice meal. He is just waiting for us to give him some ingredients and to request a meal.
Task
Given a list of ingredients (strings matching ...
14
votes
4answers
848 views
Reconstruct a 3d arrangement of cubes from two of its projections
Setup
Take the following 4x4x4 cube along with a 2D view of 3 of its faces, with a common 1x1x1 cube highlighted:
The arrows ...
10
votes
10answers
680 views
Find how many ordered pairs of integers share only one digit
Task
Your task is to make the smallest function/program that can, when gives an number N, return/print:
the number of possible choices a, b such that \$1 \leq a &...
23
votes
21answers
2k views
Four distinct 8-bit integers
Submit a well-formed program or function with usual I/O rules which satisfy the input, output, and algorithm conditions below. Shortest submission (in bytes) wins. As always, standard loopholes are ...
17
votes
20answers
2k views
Pendulum Encoding
Given a string as an input (which can be any acceptable/convenient format in your language), implement pendulum encoding. The test cases are split into individual items (which aren't quoted) for a ...
12
votes
9answers
526 views
Simulate D Flip-Flop
Objective
Simulate an edge-triggered D Flip-Flop.
What is D Flip-Flop?
A D flip-flop is an electronic digital device that outputs an inputted data (abbr. D) with synchronization to a clock (abbr. ...
3
votes
26answers
563 views
Add N numbers without using + or -
Given N integers, output the sum of those integers.
Input
You may take the integers in any reasonable format, including:
stdin
arguments
an array or list
Rules
...
-4
votes
0answers
83 views
wasting n-dimensional peanut butter
I was scraping the last peanut butter out of the jar during the Covid19 pandemic, and wondering how much of the good stuff was left down inside the jar, inaccessible but for the most desperate ...
21
votes
33answers
2k views
Vowels up, consonants down
Challenge
You will be given a string that can contain lowercase letters, uppercase letters, or spaces. You have to turn the vowels (a, e, i, o, u) in the string to upper case and consonants to lower ...
9
votes
4answers
264 views
Counting valid Binary Sudoku boards
Sequel of Counting valid Binary Sudoku rows.
Background
Binary Sudoku, also known as Takuzu, Binario, and Tic-Tac-Logic, is a puzzle where the objective is to fill a rectangular grid with two ...
12
votes
4answers
400 views
Solving the water bucket riddle!
Context
The water buckets riddle or the water jugs riddle is a simple riddle that can be enunciated in a rather general form as:
Given \$n > 0\$ positive integers \$a_1, a_2, \cdots, a_n\$ ...
12
votes
26answers
2k views
Filter an array so that duplicate items are removed
In the shortest amount of code in any programming language, filter out the duplicate items in an array of which the order is irrelevant.
Here are some test cases:
...
15
votes
10answers
1k views
Shortest total non-primitive recursive function
Natural numbers ≡ \$\mathbb{N}≡\{0,1,2,...\}\$
The submission can be either a program or a function, both cases will henceforth be referred to as "function".
The task is to golf the shortest ...
26
votes
26answers
2k views
Measure the lengths of binary patterns
Let's consider the sequence of the binary representation of positive integers (without any leading zero):
...
21
votes
19answers
4k views
Even a clock that isn't working gets the time right two or three times a day
Context
When I was a little kid, I watched a Disney movie where Goofy told his son "Boy, even a broken clock is right two or three times a day." (see this youtube clip, courtesy of @Arnauld).
...
4
votes
2answers
80 views
Tips for golfing in Pure Data
Pure data is a graphical programming language designed for audio processing. This makes it unsuitable for most general programming but especially unsuitable for code-golf.
It would then be nice to ...
15
votes
12answers
1k views
Day of the week of an ambiguous date
Goal
Write a program or function that returns the day of the week for a date, eg.
01/06/2020 -> Mon
However, it's unknown if the date is in the format mm/...
40
votes
28answers
4k views
Name your novel disease
Introduction
The current coronavirus disease is officially named COVID-19, from the 3 words corona virus disease, and the year 2019. (Technically it's coronavirus, making 2 words, but whatever...)
...
12
votes
5answers
279 views
Return a word with a prescribed sum of letters
Identify each letter of the English alphabet with the number denoting its position in the alphabet, that is,
a = 1, b = 2, c = 3, ..., z = 26
(no distinction ...
18
votes
22answers
2k views
17
votes
4answers
427 views
What can you see on a hexagonal spiral?
This code-golf challenge will have you computing OEIS sequence A300154.
Consider a spiral on an infinite hexagonal grid. a(n) is the number of cells in the part of the spiral from 1st to n-th cell ...
24
votes
23answers
3k views
Ah, why is there a bug in my program?
This challenge is inspired by @LuisMendo's MATL answer to my "binary multiples" challenge.
Task
Pick a code-golf challenge that is open and that has been posted before this one; let me call it the "...
23
votes
58answers
2k views
Numbers by Position
Numbers by Position
Challenge
Print the numbers:
1
22
333
4444
55555
666666
7777777
88888888
999999999
In that order.
I/O
Takes no input. The numbers can ...
13
votes
20answers
709 views
Quotes around sequence of chars
Challenge
Your goal is to write a function that puts quotes around a sequence of capital letters in a string.
So some examples (everything on the left (before function) and right (after function) ...
-2
votes
7answers
181 views
Generate this expanding series [closed]
Challenge
Your task is to generate a string using this sequence:
1,1,2,1,1,2,3,2,1,1,3,2,4,2,3,1,....
Which is more understandable in this format:
...
19
votes
13answers
1k views
Counting valid Binary Sudoku rows
Background
Binary Sudoku, also known as Takuzu, Binario, and Tic-Tac-Logic, is a puzzle where the objective is to fill a rectangular grid with two symbols (0s and 1s for this challenge) under the ...
17
votes
20answers
2k views
All aboard the factorial train
The system
Assume the Earth is flat and that it extends infinitely in all directions. Now assume we have one infinitely long train railway and n trains in that ...
3
votes
5answers
77 views
Find the binary period [duplicate]
We know that not all fractions have a terminating binary representation. However every fraction can be written as a leading portion followed by a repeating portion. For example \$1/3\$ starts with \$...
10
votes
1answer
143 views
Counting polyominoes on (hyper-)cubes
This challenge like some of my previous challenges will have you counting free polyforms, which are generalizations of Tetris pieces.
This code-golf challenge will have you count polyomino-like ...
