All Questions
4,642
questions
36
votes
61
answers
5k
views
Sum of primes between given range
Write the shortest code for finding the sum of primes between \$a\$ and \$b\$ (inclusive).
Input
\$a\$ and \$b\$ can be taken from command line or stdin (space seperated)
Assume \$1 \le a \le b \le ...
- 2,208
35
votes
20
answers
9k
views
Balanced Ternary Converter
Credits for the challenge idea go to @AndrewPiliser. His original proposal in the sandbox was abandoned and since he has not been active here for several months, I have taken over the challenge.
...
user16402
34
votes
16
answers
5k
views
Calculate 500 digits of pi
Write a program to calculate the first 500 digits of pi, meeting the rules below:
It must be less than 500 characters in length.
It cannot include "pi", "math.pi" or similar pi constants, nor may it ...
- 3,318
29
votes
20
answers
4k
views
Decipher a Vigenère ciphertext
The Vigenère cipher was a simple polyalphabetic cipher that basically applied one of several Caesar ciphers, according to a key. Basically the letters in the key indicate which shifted alphabet to use....
- 12.9k
28
votes
13
answers
2k
views
Tips for golfing in Swift
What are some tips for code-golfing in Swift? Its focus on safety seems to make it difficult to golf in, but that makes little tips and even more useful. Are there any features in Swift that may help ...
- 1,063
26
votes
8
answers
2k
views
All your bijective base are belong to us
Background
A bijective base b numeration, where b is a positive integer, is a bijective positional notation that makes use of b symbols with associated values of 1 to b.
Unlike its non-bijective ...
- 210k
26
votes
24
answers
2k
views
Case Permutation
Who needs to compare things case insensitively when you're able to generate every permutation of uppercase and lowercase? No one! That's the answer. No one does. Your task is to achieve this feat; ...
- 3,175
26
votes
66
answers
6k
views
Display number of occurrences for every character in an input string
The code should take a string as input from keyboard:
The definition of insanity is quoting the same phrase again and again and not expect despair.
The output ...
- 1,959
25
votes
11
answers
2k
views
Tips for golfing in Kotlin
Given Google's recent announcement of official Kotlin support for Android development, I thought it might be timely to poll the community for some awesome golfing tips for this relatively new JVM ...
- 781
25
votes
29
answers
3k
views
Different Way Forward
Given a list of integers produce a Forward Difference at a specified order/depth.
For the list of integers:
(10, 18, -12, 4, 8, -3, -5, 67, 9, 14)
The Forward ...
- 12.2k
18
votes
16
answers
1k
views
Tips for Golfing in Vyxal
Vyxal is a golfing language that has 500+ different commands (achieved through overloads), and is a known beater of Jelly, 05AB1E and most golfing languages.
Henceforth, it seems like a good idea to ...
- 32.5k
17
votes
34
answers
2k
views
Spell out the Revu'a
Actually not inspired neither by Atbash Self Palindromes nor by Generalized Gematria Calculator.
Given a string s of length n, output the Revu'a sequence, which is the first character of s, the first ...
- 29.9k
14
votes
49
answers
8k
views
Sum of positive integers. [closed]
Problem:
Given a set of integers, find the sum of all positive integers in it.
Input:
t – number of test cases [t < 1000]
On each of next t lines, an integer N [-1000 ≤ N ≤ 1000]
Output
The ...
- 497
10
votes
5
answers
2k
views
Words from periodic table of elements [closed]
Back when I was a freshman in highschool taking chemistry, I'd look at the periodic table of elements and spell dirty words out with the number of the elements (HeCK would be 2619, 2-6-19).
I was ...
- 307
235
votes
184
answers
38k
views
Evolution of "Hello World!"
This contest is officially over, the winner is jimmy23013. Congratulations!
The challenge is to make a program that prints Hello World! to stdout. The catch is that ...
- 89.3k
183
votes
29
answers
24k
views
Do you want to code a snowman?
Here is a simple ASCII art snowman:
_===_
(.,.)
( : )
( : )
Let's make him some friends. This will be the general pattern for our ASCII art snowpeople:
...
- 89.3k
124
votes
128
answers
17k
views
Make an error quine!
Your challenge: write a "program", for a language of your choice, that causes the compiler/interpreter/runtime to produce error output when compiling/running your program which is identical to your ...
- 12.3k
123
votes
95
answers
23k
views
ASCII's 95 Characters...95 Movie Quotes
Update: The winner has been decided, but the challenge is not over!
Finally, nearly 3 months after the question first started, someone has remained the last answerer for more than a week! ...
- 89.3k
96
votes
51
answers
14k
views
In Honor of Adam West
Adam West passed away, and I'd like to honor his memory here on PPCG, though I doubt he knew of our existence. While there are many, many different things that this man is known for, none are more ...
- 20.6k
75
votes
39
answers
7k
views
Stack Exchange Vote Simulator
Write a program or function that takes in a string only containing the characters ^ and v (you can assume there will be no other ...
- 89.3k
72
votes
207
answers
18k
views
The Programming Language Quiz, Mark II - Cops
A repost of this challenge. Meta discussion. Sandbox post. Body of the question similar to the original
Robber's challenge
This cops and robbers is now (08/03/2018) closed to further competing cop ...
- 49.4k
71
votes
17
answers
6k
views
Write a polyglot that prints the language's name
Your task is to write a program that executes in as many languages as possible, with as few characters as you can. To avoid trivial solutions, the program must print the name of the language it was ...
- 8,117
63
votes
44
answers
9k
views
Print the N-bonacci sequence
This isn't very widely known, but what we call the Fibonacci sequence, AKA
1, 1, 2, 3, 5, 8, 13, 21, 34...
is actually called the Duonacci sequence. This is ...
- 58.9k
59
votes
19
answers
17k
views
Biggest Irreducible Hello World
Create a program that outputs Hello, World!
The winner is the source code that is the biggest, subject to the constraint that it is irreducible
For this challenge,...
- 2,147
51
votes
11
answers
10k
views
Build a random number generator that passes the Diehard tests
While there are many code golf questions on here involving randomness, I haven't seen one yet that actually asks for building an algorithmic pseudorandom number generator. There's this one that asks ...
- 34.7k
50
votes
24
answers
7k
views
Minecraft Mirrored
This is Calvin. Just trying to get 20 rep so this user can chat in the PPCG Minecraft Server chatroom.
Write a program or function that takes in a positive integer.
If the integer is even (2, 4, 6, ....
- 617
48
votes
16
answers
6k
views
Zigzagify a Matrix
As part of its compression algorithm, the JPEG standard unrolls a matrix into a vector along antidiagonals of alternating direction:
Your task is to take a matrix (not necessarily square) and return ...
- 196k
47
votes
32
answers
7k
views
Very Simple Triangles
Write a program or function that takes in a positive integer (via stdin, command line, or function arg) and prints or returns a string of that many of these small triangles tiled together, alternating ...
- 89.3k
46
votes
146
answers
6k
views
Full Width Text
Full width text is text that has a space after every character, including the last one. For instance, the first sentence of this question becomes:
...
- 601
45
votes
84
answers
9k
views
Binary to decimal converter
Binary to decimal converter
As far as I can see, we don't have a simple binary to decimal conversion challenge.
Write a program or function that takes a positive binary integer and outputs its ...
- 46.2k
41
votes
22
answers
4k
views
Tips for golfing in Rust
While Rust is very, very rarely competitive in code golfing competitions (Java is often shorter), it can still be fun to golf in. What are some tricks for making Rust code shorter?
Please post only ...
- 71.4k
39
votes
3
answers
4k
views
Tiny Lisp, tiny interpreter
Lisp programmers boast that Lisp is a powerful language which can be built up from a very small set of primitive operations. Let's put that idea into practice by golfing an interpreter for a dialect ...
- 38k
37
votes
39
answers
4k
views
Determinant of an Integer Matrix
Given a square integer matrix as input, output the determinant of the matrix.
Rules
You may assume that all elements in the matrix, the determinant of the matrix, and the total number of elements in ...
user45941
36
votes
21
answers
4k
views
Write a Polyquine
A polyquine is both quine and polyglot.1 You are to write a quine which is valid in at least two different languages. This is code golf, so the shortest answer (in bytes) wins.
1 I made that up. Or ...
- 196k
35
votes
44
answers
5k
views
Calculate Euler's totient function
Background
Euler's totient
function φ(n) is defined as the number of whole numbers less than or equal to n that are relatively ...
- 2,272
35
votes
8
answers
5k
views
Self-Interpreting Interpreter
Based on a comment by George Edison to this question, write the smallest self-interpreting interpreter.
You may use the language of your choosing.
Empty languages do not count. Your program must be ...
- 2,092
35
votes
50
answers
10k
views
Will Jimmy fall off his platform?
Backstory
Meet my friend Jimmy:
/o\
Jimmy is a little character who likes to stand on platforms. Here's Jimmy safely standing on a platform:
...
- 2,552
34
votes
45
answers
3k
views
Calculate the prime factors
We had a prime factorization challenge a while ago, but that challenge is nearly six years old and barely meets our current requirements, so I believe it's time for a new one.
Challenge
Write a ...
- 49.9k
32
votes
77
answers
12k
views
Count the number of ones in an unsigned 16-bit integer
Write some statement(s) which will count the number of ones in an unsigned sixteen-bit integer.
For example, if the input is 1337, then the result is ...
- 1,019
32
votes
47
answers
7k
views
Implement hyperexponentiation/tetration without the use of '^' [closed]
The Challenge
Implement tetration (aka Power Tower or Hyperexponentiation) with the least amount of characters.
The Conditions
Don't use the 'power' operator or its equivalents (such as ...
- 942
30
votes
4
answers
2k
views
Create a rotating quine
A rotation of a string is made by splitting a string into two pieces and reversing their order, for example "world!Hello, " is a rotation of ...
- 748
29
votes
8
answers
3k
views
Are you in the biggest room?
Introduction
You have recently accepted a job offer at a Pretty Good Software Company. You're pretty content with the size of your office, but do you have the biggest office? Its kinda hard to tell ...
- 1,861
29
votes
5
answers
2k
views
Advanced Calculator
You must write a program that evaluates a string that would be entered into an advanced calculator.
The program must accept input using stdin and output the correct answer. For languages that do no ...
- 6,442
28
votes
47
answers
4k
views
Shortest power set implementation
Problem definition
Print out the powerset of a given set. For example:
[1, 2, 3] => [[], [1], [2], [3], [1, 2], [1, 3], [2, 3], [1, 2, 3]]
Each element is to ...
- 381
27
votes
16
answers
3k
views
Tips for Golfing in Go
What general tips do you have for golfing in Go? I'm new to Code Golfing and looking for ideas that can be applied to code golf problems in general that are at least somewhat specific to Go.
Please ...
- 729
27
votes
17
answers
13k
views
Transform number into 7-segment display pattern [closed]
Given two arbitrary numbers A,B. Print number B as a Digital LED Pattern where A is the scale.
input:
1 2320451640799518
ouput:
...
- 1,770
26
votes
6
answers
2k
views
The Coin Problem
Background
The official currency of the imaginary nation of Golfenistan is the foo, and there are only three kinds of coins in circulation: 3 foos, 7 foos and 8 foos.
One can see that it's not ...
- 42.5k
25
votes
11
answers
4k
views
Generate a Kolakoski sequence [duplicate]
Definition1
A Kolakoski sequence is a self-describing infinite sequence {kn} of alternating blocks of 1's and 2's, given by the following rules:
k0 = 1
kn = the length of the (n+1)'th ...
- 2,329
23
votes
9
answers
816
views
Given an input, move it along the keyboard by N characters
The Challenge:
Given any input that can be typed on a keyboard, move the text along by N chars.
Here is the QWERTY keyboard to be used. You can ignore the modifier keys (Shift, Caps, Enter, Delete ...
- 2,879
23
votes
4
answers
3k
views
Four fours puzzle
The Four fours puzzle is a popular recreational mathematical puzzle that involves using exactly four 4s (and no other number) and a defined set of operations to reach every number from 0 to a given ...
- 3,374