Questions tagged [code-challenge]
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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Program a Racing Car
CONGRATULATIONS to @kuroineko. Wins the bounty for excellent speed (672 moves) on the Gauntlet track.
LEADER:* Nimi scoring a lightweight 2129. Other entries are larger but showing some serious speed.
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Domino Circuits
Scoreboard
Here are the raw scores (i.e. domino counts) for VisualMelon's submission. I'll turn these into the normalised scores described below, when more answers come in. The existing solution can ...
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The PPCG Handicap System
As we all know, meta is overflowing with complaints about scoring code-golf between languages (yes, each word is a separate link, and these may be just the tip of the iceberg).
With so much jealousy ...
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Code-generator with unique characters
Challenge
Your task is to write a piece of code that outputs another piece of code. That code must in turn output yet another code until the final code outputs the integer 1. The chain ends the first ...
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Brainf*** Golfer
One of easiest code written by a programming language is a program printing sequence of characters (ex. "Hello, world!"). However, some esoteric programming languages like Brainfuck, even this ...
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Image Battle of Colours
CONGRATULATIONS to @kuroineko for the best entry and winning the 200 bounty from @TheBestOne (excellent sportsmanship!).
Write a program to colour as much of an image as possible before opposition ...
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Longest Non-Repeating Substring
Given a string as input find the longest contiguous substring that does not have any character twice or more. If there are multiple such substrings you may output either. You may assume that the ...
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How high can you go? (A coding+algorithms challenge)
Now that everyone has developed their (often amazing) low level coding expertise for How slow is Python really? (Or how fast is your language?) and How Slow Is Python Really (Part II)? it is time for ...
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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 ...
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Create a Flood Paint AI
In the game of Flood Paint, the goal of the game is to get the entire board to be the same colour in as few turns as possible.
The game starts with a board that looks something like this:
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I'm thinking of a number (Cop's Thread)
Robber's Thread here
In this cops-and-robbers challenge cops will think of a positive integer. They will then write a program or function that outputs one value when provided the number as input and ...
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A "Sorting" algorithm
There is a "sorting algorithm" sometimes called Stalin sort in which in order to sort a list you simply remove elements from the list until it is sorted in increasing order. For example the list
<...
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Rubik's Revenge [closed]
Everyone likes a good puzzle. After all, that's the basis for Code Golf and Code Challenge! What better puzzle exists than the famous Rubik's Cube? Well what else but her slightly larger sister, ...
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The Programming Language Quiz, Mark II - Robbers
Cops challenge
The Robbers' Challenge
Find a vulnerable answer. That is, an answer which hasn't been cracked yet and which isn't safe yet either.
Crack it by figuring out its language. That is, find ...
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Programming Dichotomies (Literally)
Consider a question written in plain English whose answer involves two reasonably accurate (but potentially clever) words or phrases that can be separated by the word 'and':
Q: What are the two sides ...
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R.E.P.A.I.R. T.H.E. K.E.Y.B.O.A.R.D
Sequel of this AWESOME challenge
You, a genius tech prodigy detective, have successfully disarmed the bomb and want to break into the computer. The police found the password ...
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OOP: Overlapping Oriented Programming
One of the lesser known programming paradigms which seems rather fitting for code golfing is Overlapping Oriented Programming (OOP) *. When writing partly identical code, many bytes can be saved by ...
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Underhanded Password Hashing [closed]
In the spirit of the Underhanded C Contest, I'm starting an Underhanded Code Contest. The objective of this contest is to straightforwardly implement some code, while subtly hiding a nefarious bug ...
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Pass on your radiation
The task here is pretty simple. You should write a program that takes a string as input and outputs it (that is a cat program).
Additionally when the \$n\$th byte of your program is removed (without ...
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This is the sort of challenge that bytes
I need to stop thinking of punny names
Your task is to create as many snippets (programs that have input and output built-in), functions or full programs as possible that sorts whatever your language'...
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Rand5() to Rand7() [closed]
You are provided with a function Rand5(). This function returns perfectly random (equal distribution) integers between 1 and 5.
Provide the function Rand7(), which uses Rand5() to produce perfectly ...
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Longest Prime Sums
Sandbox
There are special sets S of primes such that \$\sum\limits_{p\in S}\frac1{p-1}=1\$. In this challenge, your goal is to find the largest possible set of primes that satisfies this condition.
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Implement QuickSort in BrainF*** [closed]
As discussed in the Lounge room on Stack Overflow:
if you can't implement the Quicksort algorithm given en.wikipedia.org/wiki/Quicksort in any language you have minimal knowledge of, you might want ...
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Say Hello to the Pioneers of Computer Science
Choose your favorite famous computer scientist or computer science pioneer who was born in 1942 or earlier (as 1943 marks the start of the creation of the 'first' computer). They should have a ...
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Latin square compression
A Latin square is a square that has no repeated symbols in the rows or columns:.
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And as many Sudoku players know, you don't need ...
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Write a Quine Suite
We've had a lot of quine challenges, but a lot of the quine formats are similar, lets create some variance in our quines.
Your task is to create a selection of programs in the same language (at least ...
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Substandard deviation
The mean of a population \$(x_1,\dots,x_n)\$ is defined as \$\bar x=\frac1n\sum_{i=1}^n x_i\$. The (uncorrected) standard deviation of the population is defined as \$\sqrt{\frac1n\sum (x_i-\bar x)^2}\$...
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Can a neural network recognize primes?
Background
Recognizing primality seems like a poor fit for (artificial) neural networks. However, the universal approximation theorem states that neural networks can approximate any continuous ...
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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 ...
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Unrestricted Languages
One of my favorite types of challenges on this site are restricted-source challenges. These challenges impose a computer tractable restriction that the sources of potential answers must pass. I like ...
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Repeat your program to print Fibonacci numbers
Write a program fragment so that, when repeated N times it prints the Nth Fibonacci number. For example, if your program is print(x) then:
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Take a stand against long quine lines
or: Build a vertical quine
Inspired by Take a stand against long lines.
Your task is to build a vertical quine with as short a line length as possible.
Scoring
Shortest line length (excluding ...
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Make StackOverflow Explode (bookmarklet) [closed]
Sometimes people get frustrated on the StackExchange network (specifically SO).
Your task is to create a bookmarklet that causes StackOverflow to explode/implode/destroy in some fashion. This will ...
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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
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Concatenative counting
Your challenge is to write N snippets of code such that, when you concatenate the first K ≥ 1 together, they produce the number K. The higher N, the better. Here's the catch: you may not use any ...
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Create the slowest growing function you can in under 100 bytes
Your job is to create the slowest growing function you can in no more than 100 bytes.
Your program will take as input a nonnegative integer, and output a nonnegative integer. Let's call your program ...
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List of first n prime numbers most efficiently and in shortest code [closed]
Rules are simple:
First n primes (not primes below n), should be printed to standard output separated by newlines (primes should be generated within the code)
primes cannot be generated by an inbuilt ...
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Orientation Oriented Programming
Write a program for a specific language that in different orientations performs different tasks.
Your code should have at least two non-empty lines and at least two non-empty columns and should ...
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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 ...
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Smallest region of the plane that contains all free n-ominoes
On Math Stack Exchange, I asked a question about the smallest region that can contain all free n-ominos.
I'd like to add this sequence to the On-Line Encyclopedia of Integer Sequences once I have ...
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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 automaton ...
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What code compiles in the most number of languages? [closed]
Excluding trivial programs, what code compiles in the most number of languages?
(By "trivial" I mean to exclude answers such as the empty program or text that will be echoed directly.)
The following ...
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Count spelling errors in text; minimize the number of spelling errors in your code
Write a program or function that takes two inputs:
A text message
The dictionary of English language, as it appears in this Github file (containing about 60000 words)
and outputs the number of ...
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Adding without using a + or - sign [closed]
There have been many "Do __ without __" challenges before, but I hope that this is one of the most challenging.
The Challenge
You are to write a program that takes two natural numbers (whole numbers ...
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Display OEIS sequences
The On-Line Encyclopedia of Integer Sequences (OEIS) is an online database of integer sequences. It contains nearly 280000 sequences of mathematical interest.
Examples of sequences:
positive ...
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Add a hidden language to a polyglot
Inspired/mostly copied but I don't think it's a dupe. Also Inspired.
In this challenge, you will create polyglots that include all languages from previous answers, and another language which you won't ...
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Compounding english
A compound word is a word that contains 2 or more words in it. We can do better than that, though. We need you to create 1 (nonsensical) word that contains every word.
However, we want this word to ...
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Conway's Hello World
It is often said, that all programmers should be able to write a "hello world" program in any programming language after a few glances on that language (And quicksort after a few more glances).
As ...
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Approximate when you are going to die
A mortality table or life table is an actuarial tool that gives the probability that a person aged \$A\$ years will die in the next year, and is used to help calculate the premiums for life insurance, ...
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Short Deadfish Numbers
Deadfish is one of the best known non Turing-complete programming languages. It has only one accumulator (which starts at 0) to store data, and only four commands:
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