A code challenge is a competition for creative ways to solve a programming puzzle with an objective winning criterion not covered by other scoring tags (e.g. code-golf).
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votes
0answers
75 views
Find the result by rewriting and optimizing the code - Python [on hold]
Task
Optimize and rewrite the following code in order to find the result of Z(11223344)
Details
This challenge involves finding out what the code does and writing an optimized version.
The code ...
11
votes
1answer
169 views
Virtual Keyboard Text Input
On modern game consoles and other devices without traditional keyboards, trying to input text is a nightmare. Having to type with a few buttons and a joystick on a virtual keyboard is annoying, and I ...
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votes
0answers
72 views
I came upon this encrypted riddle [closed]
It is presented as a JSON file.
LINK
Can any of you solve it?
0
votes
0answers
51 views
A cycle of quine-like programs [duplicate]
This question asks you to write n programs, such that program 1 outputs program 2, program 2 outputs program 3, ... program n-1 outputs program n and program n outputs program 1.
However, not all of ...
17
votes
2answers
659 views
Where will the cat go? (orbital mechanics)
A nearly massless cat is dropped in space (don't worry, with a space suit and everything) at the point (x, y, z) with velocity (vx, vy, vz). There is an fixed, infinitely dense planet (with volume of ...
10
votes
4answers
268 views
Find the shortest way to advance a counter to a certain number
I have a counter. It's a small device that looks like this:
The display goes from 0000 to 9999. It has a little push-button at the top that increases the count by 1, and a little knob at the right ...
59
votes
19answers
3k views
Tweetable hash function challenge
In this code-challenge you will write a hash function in 140 bytes1 or less of source code. The hash function must take an ASCII string as input, and return a 24-bit unsigned integer ([0, 224-1]) as ...
17
votes
2answers
868 views
Fun with flags!
Write a full program with a source code of 256 bytes or less that looks at an image of a flag and determines what country that flag is from. A zip file containing the 196 different flags in the ...
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votes
2answers
198 views
Use all your language's keywords, ideally minimally [closed]
Your program must contain all your language's keywords. Ideally, you should have each one exactly once (see Scoring). Of course, this means your language must actually have keywords, so esoteric ...
15
votes
23answers
1k views
Good Old Suffix Vector
Inspired by an old manual...
The challenge
I define the ath suffix vector of b as the boolean list of length a with b trailing truthy values.
Write a program or function that, given a and b by any ...
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votes
16answers
347 views
Print all the numbers! (At least, as many as possible.) [closed]
Your task is to print a number. Simple, right? It is simple, but not as simple as this. The first answer is to print the number 1, the second answer is to print the number 2, etc.
Rules
The first ...
4
votes
0answers
209 views
Generate ASCII Art
Given a black-and-white image in any reasonable lossless format (png, ppm, etc.; filename or raw bytes) as input, output ASCII art that is as close to the input image as possible.
Rules
Only ...
27
votes
3answers
793 views
Stuffing primes in a box
Your task is write a program or function that can fill a given rectangle with
prime numbers. The width and height of the rectangle will be the input. The
output must be a list of height strings ...
13
votes
6answers
651 views
Who said that? 2016 Presidential election
In this challenge, your task is to make write a program with less than 300 characters that takes a short paragraph or a few sentences that a candidate has said and output who said it.
Input: Can be ...
7
votes
1answer
232 views
Model a probability table using 15-bit fixed probabilities
A histogram is an array of integers that counts the number of times a symbol occurs. For example, for the string "aaabbbabbdebabbbebebdbaaabbabaaaaeebeaabaaba" a histogram is a: 18, b: 18, c: 0, d: 2, ...
8
votes
5answers
369 views
Word or near-word?
Write a program or function that given a string (or your language's equivalent), determine if the string is a word, or not, and output a truthy or falsy value.
(This is not a duplicate of Is this ...
9
votes
6answers
522 views
Make a long type signature
Challenge
Find an expression, at most 100 bytes long, with the longest type signature.
Rules
Any statically typed language with type inference is allowed
The type must be non-ambiguous, but ...
187
votes
5answers
12k views
Upgoat or Downgoat?
Given an image of a goat, your program should best try to identify whether the goat is upside down, or not.
Examples
These are examples of what the input may be. Not actual inputs
Input:
Output:
...
24
votes
1answer
585 views
The PPCG Handicap System
As we all know, meta is overflowing with complaints about scoring code-golf between languages (yes, each word is a seperate link, and these may be just the tip of the iceberg).
With so much jealousy ...
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votes
1answer
200 views
“I know that language - that's Java. No? It's Perl?” [duplicate]
Introduction
A known fact is that Jon Skeet can code Perl and make it look like Java. In this challenge you will try to do something similar.
Challenge
Write a piece of code of any length that can ...
1
vote
0answers
66 views
Windows batch polyglot/hybrids challenge with any language possible [closed]
/* I hope such question is suitable for here*/
As the batch scripts are pretty limited, hybrid files that embed a code from another language into a batch file are used a lot lately.
Though usually ...
26
votes
2answers
668 views
Compress an image to a 4 KiB preview
In this challenge you will be creating an image preview compression algorithm. It's goal is to
reduce an arbitrary image file to a 4 KiB preview image, that can be used to quickly identify images
with ...
178
votes
32answers
26k views
Paint Starry Night, objectively, in 1kB of code
Below is a 386x320 png representation of van Gogh's Starry Night.
Your goal is to reproduce this image as closely as possible, in no more than 1024 bytes of code. For the purposes of this ...
15
votes
4answers
1k views
What's the Language?
Recently, the PPCG design leaderboard has been having some trouble parsing answer html headers.
In this challenge you'll be taking your own shot at parsing answer headers.
Example Test Cases
...
15
votes
1answer
243 views
Know a sequence by its subsequences
Introduction
Suppose you and your friend are playing a game.
Your friend thinks of some particular sequence of n bits, and your task is to deduce the sequence by asking them questions.
However, the ...
7
votes
6answers
322 views
The branch predictor challenge
Every day, every minute, ... every microsecond, many decisions are made by your computer. In high-level languages, these typically take the form of statements like if, while and for, but at the most ...
12
votes
2answers
305 views
A register calculator challenge
A simple register calculator
This challenge involve a simple register calculator that works in the following way:
It has some registers named A,B,C,...,Z, each of them can contain an integer, they ...
9
votes
1answer
208 views
Sort scrambled two-dimensional array filled with numbers by swapping adjacent numbers [closed]
A two-dimensional array of size n×n is filled with n*n numbers, starting from number 1. Those numbers are to be sorted per row in ascending order; the first number of a row must be greater than the ...
7
votes
6answers
334 views
Inverse symbolic calculator
This challenge is based on the idea of Plouffle's Inverter.
Write a program in any language that does the following:
Takes as input a non-negative rational number X written in decimal, for example ...
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votes
2answers
216 views
Stop Internet Warming! [closed]
Task
Write a program that will output another distinct program, and so on, while using as few distinct characters (and as few bytes) as possible.
For example, program 1 should output program 2, and ...
29
votes
4answers
443 views
Plurality Voting with Cellular Automata
There's a really important problem in cellular automata called the Majority problem:
The majority problem, or density classification task is the problem of finding one-dimensional cellular ...
224
votes
14answers
28k views
Build a Compiler Bomb
Introduction
You're probably familiar with zip bombs, XML bombs, etc. Put simply, they are (relatively) small files which produce enormous output when interpreted by naïve software. The challenge ...
15
votes
2answers
336 views
Befunge Brain Teasers
Introduction
For the ones wondering what Befunge exactly is, it is a two-dimensional stack based language made in 1993 by Chris Pressy. I made 7 brain teasers that need to be solved in Befunge-93. ...
8
votes
3answers
413 views
Egg dropping contest
Your challenge:
You are on the 0th floor of a infinitely tall building. At any floor, you can walk to the window and drop an egg. Your goal is to figure out the highest floor that the egg can ...
125
votes
91answers
11k views
What is the smallest positive base 10 integer that can be printed by a program shorter (in characters) than itself?
I think the question as above is clear, but just in case:
Write a full program (not just a function) which prints a positive base 10 integer, optionally followed by a single newline.
Qualifying ...
7
votes
4answers
444 views
Staircase Program
The challenge is simple: given two parameters, x and y, output y staircases with x steps. For example:
f(3,1) - 1 staircase with 3 steps.
_
_|
_|
f(5,2) - 2 staircases with 5 steps.
...
18
votes
10answers
2k views
Print the QWERTY keyboard using keys that are as close together as possible
Normally, challenges are scored in bytes, or sometimes Levenshtein distance, but for this one we're using keyboard distance -- the number of keys between the keys used to type the program (use the ...
23
votes
9answers
2k views
Chaining Programs
Challenge
In this challenge, you will be writing the first program, p1, of an infinite sequence of programs, in which running pn outputs/generates program pn+1. When concatenating the first n >= 2 ...
7
votes
19answers
480 views
Maximizing output from minimal input
Obviously, code golfing is all about making the most of the least code. Who really cares what the actual output is?
While we have had a challenge for highest input-to-output ratio, this is a call for ...
13
votes
4answers
584 views
An executable script file that runs on POSIX and Windows
Challenge: write a single script file foo.cmd which can be invoked from the vanilla Windows cmd.exe prompt (not PowerShell, not in administrator mode), to execute arbitrary Windows-specific code...
...
4
votes
0answers
165 views
Finding the smallest grid of squares [closed]
Inspiration from Puzzling.SE.
Suppose we have an m × n grid such that each element is a base 10 digit. We can read the numbers from such a grid so that we fix a starting element, go to one of the ...
28
votes
11answers
1k views
Find the largest gap between good primes
Following the fine tradition of questions such as Find the largest prime whose length, sum and product is prime , this is a variant on a largest prime challenge.
Input
Your code should not take any ...
58
votes
23answers
6k views
The versatile integer printer
Write a piece of code that is executable in at least three different languages. The code must output the integer 1 in language number one, 2 in language number two, 3 in language number three etc.
...
7
votes
3answers
256 views
Guess the hidden communities
Background
This challenge is about the stochastic block model.
Basically, you are given an undirected graph, where the nodes represent people, and the edges represent social connections between them.
...
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votes
1answer
126 views
Creating a colour chart in PHP will all colours [duplicate]
Now, before we begin, this has already been done here. But!, there are no PHP answers.
With that in mind, my CodeGolf is thus: create a program to show all the colours in the html CSS spectrum using ...
4
votes
0answers
182 views
Encode a steganographic encoder into a package
Introduction
By steganography we mean hiding a message along an existing text or image so the result would be unsuspicious of the existence of the original message. This challenge is about hiding ...
-4
votes
1answer
225 views
Check my program! [closed]
Challenge
Make an error-checker in the least amount of possible bytes! If you received an HTML program as a string through standard input, your program will be able to find all the errors and return ...
2
votes
1answer
203 views
Quine Pride Parade!
These days, I watched on TV a Gay Pride parade; at the time, I was thinking about quines and how they're a bit queer, outputting themselves (out of the closet?) and, well, why not combine both things ...
17
votes
7answers
630 views
Finding sum-free partitions
Executive summary
Given input k, find a partition of integers 1 to n into k sum-free subsets for the largest n you can within 10 minutes.
Background: Schur numbers
A set A is sum-free if its ...
13
votes
3answers
684 views
An optimization challenge with strange coins
You have n coins which each weigh either -1 or 1. Each is labelled from 0 to n-1 so you can tell the coins apart. You have one (magic) weighing device as well. At the first turn you can put as many ...
