For challenges that involve the physical layout or physical manipulation of source-code.
10
votes
13answers
1k views
Double-duty quine
Write a program that will output its own source code when run, and nothing else. Seems easy, right?
The catch is that when the source code is reversed, your program must output "Hello, World!" ...
12
votes
19answers
997 views
Sequential Multiplication
Your objective is to write a program that takes an input, and, when chained together N times, performs "sequential multiplication". What is sequential multiplication, you may ask? It's a sequence with ...
21
votes
14answers
1k views
Inverse function
Wouldn't it be neat if programming functions could be inverted, just like the mathematical function they implement?
Write a function (or program) that takes one input x in any form, that outputs ...
7
votes
2answers
110 views
The confused twister
The basic idea is to write a program that twists itself, and the twisted version untwists itself. The first program will just be the twisting algorithm described here, and when given its own source ...
28
votes
7answers
6k views
Build a twisted “Hello world!”
Your job is quite simple, write a program that prints Hello, world!, that when twisted creates a program that prints Twister!.
How strings are twisted
The twisting algorithm is very simple. Each ...
20
votes
2answers
421 views
Compile Regexes (By Substitution)
Your task is to compile regexes... by specifying a substitution for each character in a regex.
Regexes
The regexes support these
REGEX = (LITERAL REGEX / GROUP REGEX / STAR REGEX / ...
14
votes
1answer
686 views
90° Self-Rotating Program
Introduction
Write a complete program that rotates a rectangular block of ASCII characters 90 degrees clockwise. When the program itself is rotated 90 degrees clockwise, it rotates a block of ASCII ...
15
votes
5answers
1k views
Print a Symbolic Negative of your Code
(This is a variation on Print a Negative of your Code, which I enjoyed a lot! Thanks to Martin Büttner♦ - almost all of this text is his.)
Let's consider the symbols to be the following printable ...
25
votes
7answers
2k views
Source Code Metamorphosis
mbomb007 asked us to make a self mutilating program. Its an interesting challenge, but I personally don't like to encourage my programs to be self-mutilating. I like to think that, at the heart of ...
10
votes
13answers
1k views
Self-Mutilating Program
Simply put, your goal is to create a complete program that modifies its own source code until every character of the source is different than what it started as.
Please include the beginning source ...
27
votes
7answers
2k views
Beatles Songs and Hexagons
Write two triangle (i.e. pyramid) shaped programs.
The first one should be an upwards pointing text triangle with a minimum base width of three characters. So it would have a structure like
X
XXX
...
33
votes
8answers
5k views
40 Numbers in 9 Bytes
There are 40 ways a directed Hamiltonian path can be arranged on a 3×3 grid:
This graphic (thanks Sp3000!) shows only the 20 undirected paths. Traverse each colored line in both directions for ...
63
votes
23answers
7k views
More is less and less is more
Anybody can make the output of a program bigger by adding characters, so let's do the exact opposite.
Write a full program, an inner function or a snippet for a REPL environment in a language of your ...
1
vote
0answers
195 views
Recursive zipper reincarnation
Recursive zipper reincarnation
Objective:
Code two separate programs A and B that when concatenating their respective outputs OA + OB creates a third program: C.
When program C runs it should ...
22
votes
6answers
1k views
XOR encrypt your programs with the source of other programs
Write two programs such that when the bytes of their source code are XOR-d together it produces a third, valid program, all in the same language. The length of each of the three programs in bytes must ...
30
votes
6answers
3k views
Write A Program That Outputs Its Mirror Level
There are 95 printable ASCII characters:
!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~
In the Consolas font (the Stack Exchange code ...
26
votes
7answers
2k views
Multiplication by Self-Modification
...at least for some definition of "self-modification".
The Task
In this challenge, your task is to write three strings A, B and C that satisfy the following properties.
The string B has length at ...
15
votes
6answers
404 views
Princely Prefix by a Program in Pattern
You should write a program or function which outputs or returns as much of Chapter I of The Little Prince as it can. Your program or function has to be an M-by-N block of code containing only ...
20
votes
1answer
585 views
Programming Tetris Blocks (Literally)
In the game Tetris, there are 7 types of bricks or Tetriminoes, which are mathematically known as tetrominoes because they are all made with 4 square segments:
The have the names I, J, L, O, S, T, ...
9
votes
4answers
263 views
Row, Column, Diagonal, Block
Write a square block of code that is N characters wide and N characters tall, for some positive integer N.
For instance, your N may be 5 and the block look like this:
ThisI
sMy5B
y5Cod
eBloc
kOkay
...
21
votes
4answers
2k views
Pure Sourcery - Shaping programs that output the digits 0 through 9
Here's a pixelated 5 by 7 font for the digits 0 through 9:
.███.
█...█
█...█
█...█
█...█
█...█
.███.
..█..
███..
..█..
..█..
..█..
..█..
█████
.███.
█...█
....█
...█.
..█..
.█...
█████
.███.
█...█
...
44
votes
16answers
5k views
Sierpinskified Code
Write a rectangular block of text that when arranged into a Sierpinski carpet, using same-sized blocks of spaces for the empty portions, creates a program that outputs the iteration number of the ...
20
votes
12answers
2k views
Reading Code in 8 Ways to Output 8 Numbers
The English language and most programming languages are written and read from left-to-right, top-to-bottom, but that needn't be the case.
In fact for the block of text
ABC
DEF
I can think of eight ...
32
votes
8answers
4k views
One hundred passwords
I have one hundred vaults, each one within another. Each vault has a password, consisting of a single number.
95 43 81 89 56 89 57 67 7 45 34 34 78 88 14 40 81 23 26 78 46 8 ...
29
votes
24answers
2k views
Join N copies of a snippet to produce N^2 characters
Write the shortest snippet of code possible such that, when N copies of it are strung together in a larger program, the number of characters output is N2. N is a positive integer.
For example if the ...
4
votes
0answers
81 views
Resistent counter [duplicate]
You just have to ouput exactly all the numbers from 1 to 10 separated by spaces.
Your programme should work all the times even if a random character is deleted before compiling/interpreting.
This is ...
16
votes
36answers
3k views
The Jigsaw Code Puzzle
This is an answer-dependent challenge! The order of answers matters, and your exact task depends on the last answer that was posted. You might want to sort the answers by oldest.
Let's piece ...
7
votes
4answers
454 views
Write a binary counter in quine
Write two code fragments, which we will call s_zero and s_one.
Program (l, n) consists of l copies of s_zero and s_one corresponding with the digits of n in binary, padded with s_zero on the left.
...
10
votes
4answers
672 views
Put the line in the code you nut and shake it all up
Using one programming language write 5 single-line programs, each of which outputs a different line of the first verse to Harry Nilsson's 1972 song "Coconut" when run individually:
Brother bought ...
1
vote
4answers
399 views
All those duplicate questions deserve duplicate code to show them off
All those questions that are duplicates... Ignored and marginalized by society. It is just not... right. We have to do something. There surely must be love for them too.
They feel appreciated if a ...
6
votes
3answers
428 views
Retrograde morse (d)e(n)coder
This question is inspired by retrograde music. Retrograde music is a piece of music that can both be played normally (from the beginning to the end) as reversed (from the end the beginning). A similar ...
10
votes
1answer
440 views
Code a Code Slidey Puzzle!
The most recognizable sliding puzzle is the fifteen puzzle. It has a 4 by 4 grid, 15 tiles, and one empty grid space. The tiles can only move into the empty space and must always be in line with the ...
12
votes
1answer
210 views
Golf some quine stripes in different languages
You will choose m languages and write n programs in each language, each with length n*m. The kth program should output the kth character of each program, ordered by the program number.
For example, ...
18
votes
9answers
1k views
Caesar-Cypher-Mania
The Caesar Cypher is a very simple substitution cypher where each letter is shifted by a fixed offset (looping around Z to A). Similarly, we can also a Caesar cypher for the set of printable ASCII ...
50
votes
20answers
5k views
Significant Whitespace
We define whitespace to be any of the three characters, tab (0x09), newline (0x0A) or space (0x20).
For this challenge, you're to write two programs or functions in the same programming language, ...
21
votes
6answers
2k views
Mutual Negative Quines
This was inspired by Print a Negative of your Code and Golf a mutual quine.
Consider a rectangle of characters, that meet the following restrictions:
Consists solely of printable ASCII characters
...
66
votes
17answers
13k views
Print a Negative of your Code
Consider a square of printable ASCII characters (code points 0x20 to 0x7E) for side length N, like the following (here, N = 6):
=\
g \
7
m+y "g
L ~
e> PHq
We also require each row ...
19
votes
4answers
2k views
The Fatal Error Challenge
Objective
Write a routine that accepts a string of printable ASCII characters, s, and returns a string containing the same characters as s, reordered so that no two-character substring appears more ...
16
votes
3answers
2k views
Onion Programming
Using only printable ASCII (hex codes 20 to 7E), write a square N×N core program without comments that is surrounded by 4 more layers, creating a (N+8)×(N+8) square program (N > 0). For N = 3 the ...
14
votes
3answers
1k views
Choose-Your-Own-Language Code
Let's take a grid of 16x16 printable ASCII characters (code points 0x20 to 0x7E). There are 30-choose-15 paths from the top left to the bottom right corner, making only orthogonal moves, like the ...
8
votes
5answers
444 views
Code Crosswords - Solutions
This is the companion question for Code Crosswords. Robber answers go here.
See Where should we put robbers? for meta-info.
20
votes
7answers
2k views
Code Crosswords
This is a cops-and-robbers challenge. Answer here if you are a cop (crossword maker), answer the companion question if you are a robber (crossword solver). You may take on both roles.
Cops (Puzzlers)
...
31
votes
18answers
4k views
Jumblers vs Rebuilders: Coding with Tetris Bricks
In traditional Tetris, there are 7 distinct tetromino bricks, each denoted by a letter similar to its shape.
#
# # #
# ## # # ### ## ##
# ## ## ## # ## ##
I O ...
15
votes
3answers
1k views
Write a square program that outputs the number of times it has been “unrolled”
Consider a square block of text, N characters wide by N tall, for some odd integer N greater than 1.
As an example let N = 5 and the text be:
MLKJI
NWVUH
OXYTG
PQRSF
ABCDE
Notice that this is the ...
9
votes
4answers
816 views
Anagramming Code
Let's try this again.
The object of this contest is to make two pieces of code that are anagrams of each other (the two must contain the same bytes in a different order), and they will do the ...
2
votes
3answers
218 views
Writing Phrases with Code [closed]
This is my first contest, so please tell me what I can do to improve.
The object of this contest is to write program lines in your language of choice that are both valid code and self-descriptive in ...
24
votes
5answers
2k views
Radioactive Quines
A radioactive quine is a quine-like program that has an even number of characters and, when run, outputs itself with exactly half of its characters removed.
The output itself may be a radioactive ...
17
votes
6answers
1k views
Run the Nth characters to get N
Write the shortest program possible such that when you combine the first character and every Nth character after it into a new program, the output is N. This must work for N = 1, 2, ..., 16.
Another ...
32
votes
6answers
3k views
Code that runs the Game of Life on itself
Write two rectangular blocks of code, each w characters wide and h characters tall, that implement Conway's Game of Life when arranged in a grid. (w and h may be any positive integers)
For example, ...
23
votes
23answers
4k views
Program your favorite phrase
Pick a quote or phrase that is exactly 5 words long, such as Programming puzzles and code golf!.
Write a program that, when appended to itself n times, outputs the first n + 1 words of your phrase in ...
