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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4
votes
0answers
60 views

Using dictionaries, thesauruses, and similar databases, construct as large of a “See also” loop as possible [on hold]

As I'm sure many of you know, synonyms can range from very similar to not-so-similar-but-I-can-see-how-it's-similar. It's common for dictionaries to use "See also" to denote occurrences of words that ...
17
votes
22answers
3k views

Valid Through The Ages

Inspired by this question on SO, your task is to produce a program that is valid in (at least) two major versions of your chosen language that produce different output. Rules Any language that has ...
14
votes
17answers
2k views

Draw a regular polygon

The goal of this code golf is to draw a regular polygon (one with equal side lengths) given the number of sides and radius (distance from center to vertex). The number of sides and the radius can be ...
-2
votes
0answers
128 views

Parameter passing exercise [closed]

Task Write a program that behaves differently according to how the compiler approaches parameter passing. Treat these cases as imaginary: "if I had a compilator that passes by reference" or "if the ...
23
votes
6answers
808 views
+100

Hangman solver king-of-the-hill

You are required to write a Hangman solver. Testing against this English word list[1], the solver that solves the most number of words wins, with the number of total incorrect guesses being the ...
11
votes
4answers
1k views

Shortest code to write longest code

Your challenge is to create a shortest code in your language of choice which writes on a .txt file the longest code to multiply two numbers by taking two numbers as input and output the answer. NO ...
12
votes
1answer
673 views

Juggling by Numbers

Your task is to generate a valid juggling pattern by completing a given template. But first, you probably need to know how such a pattern is denoted. Introduction to Siteswap Siteswap is the ...
16
votes
3answers
508 views

Tower of Hanoi Sort

Write a function/subroutine to sort a list of integers, Tower of Hanoi style. You will be given a stack of integers. This is the main stack. You are also given two more helper stacks. These helper ...
18
votes
29answers
3k views

Sort-a-number. Sorta

Inspired by the ill-fated sorting-a-numbers-digits-without-using-an-array, but I thought it made a better code golf than SO question. Given a positive integer, sort the digits in that integer. ...
3
votes
1answer
397 views

Ration your integers and feed the people [closed]

It is wartime, and rationing is taking place in certain regions of your country. Your cities' region is one such region. The city chooses to give everyone the same amount, but in reality, larger ...
14
votes
7answers
2k views

The Random Quine

Write a program that is capable of randomly generating itself. It must do this based on the tokens used in its source code. If your program's source code is composed of 50 unique tokens and is 60 ...
10
votes
1answer
538 views

How many Sudoku puzzles exist?

This is not a Sudoku solver, nor a Sudoku checker. Your challenge is to write a function or script that, given as input the "block" size of a 2D Sudoku puzzle (which is 3 for the classic 9x9 board, 4 ...
10
votes
6answers
319 views

Print a specific value in this generated binary matrix

Suppose we define an infinite matrix M, on N^2 -> {0, 1} (where N starts from 1 instead of 0) in this manner: M(1, 1) = 0. For every x > 1, M(x, 1) = 1 if x is prime, and 0 otherwise. For ...
10
votes
14answers
1k views

Golfed+Fast sorting in C

[Latest update: benchmark program and preliminary resuls available, see below] So I want to test the speed/complexity tradeoff with a classic application: sorting. Write an ANSI C function that ...
1
vote
7answers
343 views

Cross Language Troll [duplicate]

The Setup Jim the student who attempts to use Stack Overflow to do his homework has asked how to get his program to say "Hello World" in under 100 lines of code, you decide mere mortal trolling is not ...
4
votes
1answer
338 views

ASCII Art Generator

Your goal is to write a program / script which "converts" real images into ascii art. General: Your program will get a path to a image file over stdin or as parameter (whatever you prefer). The ...
-2
votes
4answers
174 views

Calculate Fibonacci series from nth term to mth term [duplicate]

Your goal is to calculate the sum of Fibonacci series from n th term to m th term (including both terms). No use of / * % or mathematically what they are in your language of choice. No use of ...
5
votes
3answers
647 views

Eiffel Tower in 3D

This challenge asks you to draw the Eiffel Tower in 3D using different ASCII characters to represent the different sides, similar to this cube: @@@ @@@@@@@@@ @@@@@@@@@@@@@@@ ...
-4
votes
4answers
221 views

“Hello, world!” with n distinct characters

Write a series of programs in the same language that print “Hello, world!” using n distinct source characters, where n is in [1..10] inclusive (“distinct” meaning that duplicate characters are ignored ...
4
votes
4answers
289 views

Partially Solve the halting problem for brainf***

To solve the Halting Problem you are given a description of a program, and must determine whether or not it will ever finish. You can never do this for all programs. Yet for programs like (in ...
36
votes
1answer
863 views

Minimal keystrokes needed to type a given text

We all know that programmers tend to be lazy. In order to maximize your free time, you decide to write a program that outputs a minimal number of keystrokes for text fed into it. Input: Text that ...
8
votes
2answers
349 views

Robots! Collect these pickles!

I seem to have gotten myself into a bit of a pickle. Literally. I dropped a bunch of pickles on the floor and now they're all scattered about! I need you to help me collect them all. Oh, did I mention ...
22
votes
4answers
2k views

Implement ROT-47… in ROT-47

Challenge: Implement ROT-47 in code that works as both itself and as the ROT-47 version of itself. Scoring: Your score is calculated as a percentage of used, ROT-47 eligible bytes in total of both ...
53
votes
64answers
8k views

Call a method without calling it

Inspired by a now deleted StackOverflow question. Can you come up with a way to get a particular method executed, without explicitly calling it? The more indirect it is, the better. Here's what I ...
2
votes
1answer
257 views

Determining part of speech of most words [closed]

Write a program to output the part of speech of any word inputted to it. I doubt that anyone could get a perfect algorithm, so I will give the code a batch of words in order to ascertain what ...
-5
votes
5answers
140 views

Append to an external text file - Code Golf [closed]

The Challenge You must create a function that can append to an external text (.txt) file. No text needs to be appended, it is just the function that matters. Any language is welcome and you can use ...
-6
votes
3answers
311 views

Make a golfing language [closed]

In this challenge, you get to create a language. Although you have to provide code in other languages, you will only be rated based on the language. Here are the requirements. You must invent a ...
12
votes
9answers
709 views

Kind of meta: get the longest of the shortest answers

Your task - if you accept it - is to write a program which helps understanding my proposal on meta by calculating the winner of a code-golf-reversed competition. Of course, answers to this question ...
4
votes
2answers
348 views

Analysing the most common words in a text, and replacing them with a single byte

This is a very crude text encoding algorithm I came up with the other day. It won't work if the text has more than 256 different characters in it – but it does support Unicode, at least in my Python ...
5
votes
2answers
192 views

2D javascript table graphics

The challenge Make a JavaScript program that can use a HTML table as a canvas, having each cell a pixel. You can either input the position and color values in a form or by using the console. Score ...
11
votes
8answers
1k views

Is it a prime? w/o math

Write a program or function in any language that tells if the input is a prime number. The input is a string representing a natural number in base-10. The output is one of the two strings "Prime" or ...
1
vote
4answers
312 views

Theoretical algorithm to compute Graham's number

Graham's number G is defined in that way: 3^n = 3*..n times ...*3 3^^n = 3^(3^n) 3^^^n = 3^^(3^^n) 3^^^^n = 3^^^(3^^^n) g1 = 3^^^^3 g2 = 3^^...g1 times^^3 g3 = 3^^...g2 times^^3 ... G = 3^^...g63 ...
2
votes
0answers
191 views

Shortest Sub Segment Problem [closed]

Given a paragraph of text, and a list of k words, write a program to find the first shortest sub-segment that contains each of the given k words at least once. The length of a segment is the number of ...
8
votes
3answers
458 views

Write code to determine the accepted answer

Post an answer to this question that evaluates any answer to this question and determines whether it wins. Who wins: Winner is the answer that wins according to the most answers at 1700 UTC, ...
-3
votes
2answers
303 views

Make “The day we fight back” Logo

Seeing that Feb. 11, 2014 is being celebrated as "The day we fight back", your code-challenge is to make a Day we fight back Logo, similar to the once shown below, in the language of your choice. ...
6
votes
2answers
231 views

Eco-ize data for printing

Inspired by ecofont. Given a string containing # and , output it more eco-friendly by cutting out circles, while keeping it "recognizable" (defined later, in the Circles section). # represents ...
6
votes
1answer
253 views

Graphical, networked, two-(human)-player Tic-Tac-Toe

Create a Tic-Tac-Toe game that allows two human players to play against each other using two networked devices. Requirements: Network play. Program must let both players know whose turn it is. ...
3
votes
2answers
254 views

Build a program that creates a minimal one-ohm resistor diagram for a given resistance

You are a contractor for a company who designs electrical circuits for the various products they make. One day, the company accidentally gets a huge shipment of one-ohm resistors and absolutely ...
6
votes
2answers
145 views

Inverse CIDR whitelist

The task The task is to write a program that turns a list of IPv6 addresses into a shortest possible list of CIDR masks, such that everything but those IPs is matched. CIDR masks A CIDR mask ...
3
votes
6answers
325 views

Rotate simple ASCII art

This is similar to a previous question on this site, but with much simpler rules, so we should get much shorter results (in bytes): Input: ASCII art with only two possible characters: space and ...
0
votes
0answers
182 views

Find the best path in a “match-3” game

Suppose you want to cheat in a "match-3" game. In this "match-3" game: In each turn you can move a gem along a path. For example, you can move a gem right-right-down, as in A. (The gems are ...
5
votes
5answers
444 views

Add an integer to a set and take it back out

Definition: a set is a datatype which allows testing of inclusion ("does set X contain element Y?") but does not have order. Its size is the number of distinct elements it contains. Define an ...
5
votes
4answers
447 views

Golf with a bowling ball: hello world with high complexity yet short code

In this challenge, you must write a Hello World program that is both short and complex. We measure complexity by Cyclomatic McCabe complexity, and length by the number of bytes (not characters). ...
21
votes
12answers
1k views

Smallest chess board compression

Write an algorithm or program that can encode and decode a chess board. The goal is to make the smallest representation of a chessboard that could be used (once decoded) to determine all movement ...
13
votes
10answers
2k views

Insanity Check Program

Insanity: doing the same thing over and over again and expecting different results. Write a program that just throws an exception (runtime error) each time it is run. The challenge being to have ...
1
vote
1answer
143 views

Alphanumeric recursive meeting

This challenge is about finding the perfect match between your program sourcecode and the output from your program. Scoring table for the output: Each letters (a-z|A-Z) : `a` or `A` ...
0
votes
7answers
173 views

Find all problems that equal an integer [duplicate]

In this challenge, your job is to write a program that allows a user to enter an integer. Then, the program must find all the possible ways of multiplying two numbers to get the user's integer. Rules: ...
7
votes
5answers
256 views

Metapoem equinox

Objective: Write one program that outputs sourcecode for another program that outputs words. General information: Any programming language. Rules: Your programs should not take any input. ...
20
votes
6answers
797 views

Wikipedia: Philosophy!

As many geeks may know most pages (95% i think) on wikipedia eventually lead to Philosophy like this: Click on the first non-italic or in parentheses link that is to another normal article: (i.e. not ...
3
votes
6answers
337 views

Compute every combination of operations written in a .TXT file

Your task is to create a program that computes every combination of the operations written in a .TXT file. Example TXT File: 1 + 2 / 3 Example Output: 1+2/3=1 1+3/2=2 2+1/3=1 2+3/1=5 3+2/1=5 ...