Questions tagged [code-golf]

Code-golf is a competition to solve a particular problem in the fewest bytes of source code.

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41
votes
69answers
7k views

Is it a leap year?

This challenge is quite simple. You will take an input which will be a year from 1801 to 2400, and output if it is a leap year or not. Your input will have no newlines or trailing spaces: ...
36
votes
47answers
6k views

Catalan Numbers

The Catalan numbers (OEIS) are a sequence of natural numbers often appearing in combinatorics. The nth Catalan number is the number of Dyck words (balanced strings of parenthesis or brackets such as ...
21
votes
7answers
2k views

Tips for golfing in Julia

What general tips do you have for golfing in Julia? I'm looking for ideas that can be applied to code golf problems in general that are at least somewhat specific to Julia (e.g. "remove comments" is ...
25
votes
8answers
1k 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 ...
16
votes
31answers
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 ...
9
votes
5answers
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 ...
27
votes
23answers
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; ...
17
votes
25answers
5k views

The Work Day Countdown

I just had a genius idea for making the work-life easier - a countdown to a specific date which only counts workdays. The basic task is to create a countdown to a specific date which only includes ...
143
votes
244answers
27k views

Unscramble the Source Code

Note: This challenge is now closed to new cop submissions. This is to ensure that no one can post submissions that only remain uncracked because there aren't enough robbers interested in the challenge ...
119
votes
185answers
30k views

Sing Happy Birthday to your favourite programming language

Your favourite programming language has just had a birthday. Be nice and sing it the Happy Birthday song. Of course you should accomplish this by writing a program in that language. The program takes ...
43
votes
37answers
15k views

Draw A Sierpinski Triangle

The Sierpinsky Triangle is a fractal created by taking a triangle, decreasing the height and width by 1/2, creating 3 copies of the resulting triangle, and place them such each triangle touches the ...
86
votes
265answers
16k views

Create output twice the length of the code

The Challenge Write a complete program that writes twice as many bytes to standard output as the length of the program. Rules The program must write ASCII characters to the standard output. The ...
32
votes
12answers
2k views

Tips for golfing in vim

I've recently realized how vim works great for golfing, especially for kolmogorov-complexity. Also, according to meta vim is a perfectly acceptable 'programming language' at least, for the scope of ...
25
votes
7answers
3k 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 ...
65
votes
36answers
11k views

Enlarge ASCII art

In this challenge, you must take multiline ASCII art as input, such as: ...
28
votes
5answers
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 ...
28
votes
37answers
5k views

Implement hyperexponentiation/tetration without the use of '^'

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 ...
56
votes
35answers
6k 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 ...
45
votes
18answers
5k views

Sᴍᴀʟʟ Cᴀᴘꜱ Cᴏɴᴠᴇʀᴛᴇʀ

Portable Spec. Iɴꜱᴘɪʀᴇᴅ ʙʏ @ConorO'Brien's ᴜꜱᴇʀɴᴀᴍᴇ. Aʟꜱᴏ ᴛʜᴀɴᴋꜱ ᴛᴏ @Dᴏᴏʀᴋɴᴏʙ ꜰᴏʀ ꜱʜᴏᴡɪɴɢ ᴍᴇ ᴛʜᴇ ᴇxɪꜱᴛᴇɴᴄᴇ ᴏꜰ ǫ ᴀɴᴅ x. Sᴍᴀʟʟ ...
35
votes
78answers
7k views

Notcalc (Calculate the wrong answer)

Goal: Given two natural numbers (integers from 0 to infinity), output a number that is not the sum of those numbers, but is a natural number. Example solutions (TI-Basic): ...
30
votes
41answers
9k 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: ...
22
votes
11answers
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 ...
22
votes
10answers
2k views

Tips for golfing in Lua

What general tips do you have for golfing in Lua? I'm looking for ideas that can be applied to code golf problems in general that are at least somewhat specific to Lua (e.g. "remove comments" is not ...
21
votes
54answers
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 ...
63
votes
47answers
6k views

N-dimensional N^N array filled with N

In: Enough memory and a positive integer N Out: N-dimensional N^N array filled with N, where N^N means N terms of N-by-N-by-N-by... Examples: 1: [1] ...
33
votes
20answers
2k 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 ...
29
votes
8answers
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 ...
21
votes
6answers
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 ...
20
votes
5answers
2k views

Calculate π with quadratic convergence

Write a function or complete program that takes a positive number n and performs n steps of an iterative algorithm for ...
16
votes
7answers
734 views

Tips for golfing in Prolog

What general tips do you have for golfing in Prolog? I am looking for ideas that can be applied to code golf problems in general that are at least somewhat specific to Prolog (e.g. one letter ...
34
votes
17answers
6k 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. ...
21
votes
25answers
3k views

Code-Golf: Permutations

Write a function that takes as input a set of integers (can be a list, array or any other container with distinct numbers), and outputs the list of all its permutations. Python (95 chars): ...
13
votes
6answers
1k views

Golf me an ASCII Alphabet

Don't you find that reading simple text isn't appealing enough? Try our ...
50
votes
24answers
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, ....
23
votes
47answers
4k views

Sort an Integer List

The Challenge It's quite simple really, sort a list of numbers. Details You must sort a list of numbers in ascending order, without using any built-in sorting functions/libraries/etc (i.e. ...
11
votes
16answers
2k views

Give me the Gray Code list of bit width n

The Gray Code is a sequence of binary numbers of bitwidth n where successive numbers differ only in one bit (see example output). Reference Example input: ...
178
votes
28answers
20k 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: ...
47
votes
6answers
8k views

Golf a number bigger than TREE(3)

The function TREE(k) gives the length of the longest sequence of trees T1, T2, ... where each vertex is labelled with one of k colours, the tree Ti has at most i vertices, and no tree is a minor of ...
64
votes
42answers
5k views

Check if words are isomorphs

Two words are isomorphs if they have the same pattern of letter repetitions. For example, both ESTATE and DUELED have pattern <...
46
votes
47answers
9k views

Display random colored pixels

I've always liked screens full of randomly colored pixels. They're interesting to look at and the programs that draw them are fun to watch. The challenge Fill your screen, or a graphical window, ...
39
votes
9answers
5k views

Text compression and decompression — “Nevermore.”

With the recent discussion about the use of compression tools in code golf, I thought it would be a nice challenge to write your own text compressor and decompressor. Challenge: Write two programs: ...
43
votes
37answers
15k views

Outputting ordinal numbers (1st, 2nd, 3rd)

I would like to generate (as a return result of a function, or simply as the output of a program) the ordinal suffix of a positive integer concatenated to the number. Samples: ...
33
votes
3answers
2k 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 ...
20
votes
19answers
3k views

Basic Calculator

You must write a program to evaluate a string that would be entered into a calculator. The program must accept input and output the correct answer. For languages that do not have standard input/...
33
votes
9answers
3k views

Who's that Pokémon?

Input: an integer N between 1 and 151 Output: the Nth Pokemon. Rules You may use one data file. You may not use any already made data decompression algorithms. This includes libraries and other ...
22
votes
4answers
2k 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 ...
47
votes
32answers
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 ...
40
votes
78answers
10k views

Add without addition (or any of the 4 basic arithmetic operators)

Problem: Your goal is to add two input numbers without using any of the following math operators: +,-,*,/. Additionally, you can't use any built-in functions that ...
65
votes
20answers
7k views

Just repeat yourself

Write a program that outputs Do not repeat yourself! Your program code must respect the following constraints : its length must be an even number each ...
43
votes
55answers
10k views

I reverse the source code, you negate the output!

Your task, if you wish to accept it, is to write a program that outputs a non-zero number(can be integer or float). The tricky part is that if I reverse your source code, the output must be the ...

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