# All Questions

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### How many Jimmys can fit?

In this simple but fun challenge, you were asked to determine if Jimmy would fall of their platform. Jimmy has three body parts /, ...
346 views

### Print the previous answer in reverse - with a catch (pt. 2)

Your challenge is very simple: output the previous answer, in reverse. However, as with this similarly-titled question, there's a catch: in this case, you cannot use characters from the answer before ...
315 views

### Print the previous answer in reverse - with a catch [duplicate]

Your challenge is very simple: output the previous answer, in reverse. However, as with this similarly-titled question, there's a catch: in this case, you can only use characters from the answer ...
832 views

### Multi-user CRUD: Valid, Problem, or Error?

Introduction: Ever used Dropbox with some other people and you both modified the same file? Ever had a multi-user application with a relational database, and two people were modifying (or worse, one ...
1k views

### n-level Ouroboros Quine

This 128-language quine ouroboros (a program which outputs a program in another language, which outputs a program in yet another language, (125 languages later), which outputs the original program) is ...
233 views

### Smallest web server [closed]

Create your smallest web server in your preferred language! Requirements Must respond to atleast 1 type of request (get,post,patch,delete), with a specified string. Smallest implementation wins! *...
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: ...
110 views

### Report divisibility with arithmetic integer operations only [closed]

Given two numbers, the first is greater than the second, check whether the first number is divisible by the second without a remainder. If divisible, answer "yes"(...
8k views

### Machine Learning Golf: Multiplication

I'd like to propose a different kind of golfing challenge to this community: (Artificial) Neural Networks are very popular machine learning models that can be designed and trained to approximate any ...
186 views

### Is this number a palindrome? [closed]

Input A single integer in your language's preferred format. This format is non-negotiable (no input as strings, arrays of digits, etc.), but standard I/O formats do apply if otherwise it would be ...
123 views

### Generating all Character possibilities with two characters [duplicate]

Introduction So the Challenge is to give out all combinations with two Inputs. The length of the string is also optional and you should be able to edit this. I've selected this channel because I ...
14k views

### Do the 26 richest billionaires own as much wealth as the poorest 3.8 billion people?

Introduction: A few days ago I read this post with the same title when I came across it in the HNQ. In this question it is being discussed if the claim of president-candidate Bernie Sanders, who ...
192 views

### Add 2 positive integers by playing with bits [closed]

Given 2 positive integers in any format you'd like, return their sum using only logic gates and bit shifts (see example below). Don't worry about overflow. EDIT: Using pre-written addition is ...
4k views

### Find the closest HTML colour name

Input A single hex 6-digit colour code, capital letter, without #. Can also be a 24-bit integer if you prefer. Output The closest HTML color name (e.g ...
2k views

### Find the closest three-digit hex colour

In CSS, colours can be specified by a "hex triplet" - a three byte (six digit) hexadecimal number where each byte represents the red, green, or blue components of the colour. For instance, ...
300 views

### Golf my iteration function

Here is my ungolfed Ruby code for a function I want to try and golf: ...
468 views

### Implement a strongly Darboux function

According to Wikipedia, a strongly Darboux function is one for which the image of every (non-empty) open interval is the whole real line In other words, a function $f$ is strongly Darboux if ...
3k views

### A quine of sorts

Given a string x, output the characters in x sorted according to the order of appearance in your source code. Examples ...
4k views

### Two palindromes are not enough

Some numbers, such as $14241$, are palindromes in base 10: if you write the digits in reverse order, you get the same number. Some numbers are the sum of 2 palindromes; for example, $110=88+22$, ...
343 views

### Write the shortest O(n^2) sorting algorithm [closed]

Write a sorting algorithm for a list of integers that has an average performance of O(n^2). This is code-golf, so the shortest code in bytes wins. RULES: The characters wasted for the declaration ...
3k views

### Prime parity peregrination

The purpose of this challenge is to graphically depict a walk on the plane, where the direction of each step $k$ is determined by the primality of $k$ and the parity of its binary expansion. ...
7k views

### Golf the smallest circle!

The problem: Given a non-empty set of points in the Cartesian plane, find the smallest circle that encloses them all (Wikipedia link). This problem is trivial if the number of points is three or ...
638 views

### Output the nth 'boring' number

There are 9 main types of numbers, if you categorise them by the properties of their factors. Many numbers fall into at least one of these categories, but a few don't. The categories are as follows: ...
142 views

### Letter Boxed, part 2: this time, solve it

This challenge is a sequel to Letter Boxed Validator. The New York Times has a daily online game called Letter Boxed (the link is behind a paywall; the game is also described here), presented on a ...
259 views

### Inverse-quotes-quine, inverted (pt. 2)

Based on a comment by Jo King on my previous question (called 'Inverse-quotes-quine'), I present this new question. The rules are similar, but just, the opposite: If your program is run normally, all ...
3k views

### Analog is Obtuse!

An analog clock has 2 hands*: Hour and minute. These hands circle the clock's face as time goes by. Each full rotation of the minute hand results in 1/12th of a rotation of the hour hand. 2 full ...
458 views

### Number conversion

Assume that there is a number a. In every conversion of that number, the number can either convert itself to its value plus the value of one of its digits, or ...
4k views

### Alphabet completion rate

Introduction How much of the English alphabet does a given string use? The previous sentence uses 77%. It has 20 unique letters (howmucftenglisapbdvr), and 20/26 ≃ 0.77. Challenge For an input ...
2k views

### Inverse-quotes-quine

The prospect of this challenge is: If your program is run normally, all of the code in the speech marks (" - double quotes) should be printed. If your program is ...
173 views

### Fastest way to iterate over sublattice of discrete lattice

I need to construct a functor that iterates over the linear representation of a sub-lattice of size $d_x,d_y,d_z,d_q$ embedded in a lattice of size $n_x,n_y,n_z,n_q$. The sub-lattice corner is ...
3k views

### Is my Rep in Stack-Exchange Form?

Premise: Your reputation is in Stack-Exchange Form if it can be represented by decomposing your medal counts (gold, silver, and bronze counted separately) into their base-10 digits and joining them ...
845 views

### Find the diameter of a word graph

Introduction A popular word puzzle is to convert one word into another via a series of steps which replace only one letter and which always result in a valid word. For example, BAG can be converted ...
6k views

### Impossible darts scores

I was surprised to not find this asked already, though there is a great question on darts checkouts: Darts meets Codegolf Your challenge is to calculate which scores are not possible with 'n' darts ...
241 views

### Convert a string containing integers to list of integers

What is the shortest way to convert a string containing integers separated by spaces to a list of integers? input : "-3 1 5 8 10" output : [-3, 1, 5, 8, 10] I regularly face this situation and I ...
2k views

### Find the C-factor of a vote

In this challenge you will be determining how controversial a vote is, given an array of other votes, by figuring out a number called the C-factor. What is the C-factor, you ask? Well, imagine you've ...
438 views

### Distributing parliament seats

Introduction In a general election, one would like to calculate a constant price per parliament seat. This means that for N >= 0 seats to be distributed and a ...
5k views

### Count All Possible Unique Combinations of Letters in a Word

You are given a string, which will contain ordinary a-z characters. (You can assume this will always be the case in any test, and assume that all letters will be lowercase as well). You must ...
974 views

### Subtract the Folded Matrix

Challenge: Given an NxN matrix where $N\geq2$ and one of eight distinct 'folding options', output a 2D array/list with the subtracted values. The eight folding options are: left-to-right; right-to-...
6k views

### Cut the gold chain

A traveler needs to stay for n days in a hotel outside town. He is out of cash and his credit card is expired. But he has a gold chain with n links. The rule in this hotel is that residents should ...
385 views

### Print the total length of all “quoted” characters

Rules In this challenge, I'm going to redefine the definition of "quotes" a bit. Quotation marks (AKA quotes) are any identical characters used in pairs in various writing systems to set off direct ...
2k views

### Print 'A' 1000 times with BrainFuck

What is the best BrainFuck code (in terms of code size) to print 'A' 1000 times ? My approach is: set 'A' to p[0] set 255 to p[1] to display 255 'A', 3 times set 235 to p[1] to display 235 'A' This ...
187 views

### Reroute the Path

Given a grid of directions and a start and end position, determine the minimum number of substitutions in the direction grid that needs to be made to complete the path between the two points. The grid ...
2k views

### Print the new site header

The new site header has some bits of source code from various questions as the background. Here are the first 3 lines: ...
1k views

### Fill the maze with a wall-following Snake until it gets stuck

Make a snake fill any maze (until it gets stuck). The snake The snake starts at a given starting point, pointing EAST. It moves by always having a wall or a part of its body immediately to the LEFT ...
3k views

### First occurrence in the Sixers sequence

The Sixers sequence is a name that can be given to sequence A087409. I learned about this sequence in a Numberphile video, and it can be constructed as follows: First, take the multiples of 6, ...
133 views

### Pandemic Outbreak Calculator [closed]

In the board game Pandemic, an outbreak occurs when a city contains more than 3 disease cubes. When the outbreak occurs, any disease cubes in the city in excess of 3 are removed, and each city ...
441 views

### FizzBuzz but time-based

Make a program that outputs the number of seconds from the beginning of today (00:00:00 of the day you run it) to the second you ran it. However, if this number is divisible by three, print ...
213 views

### The year counter is here [closed]

Create a program that, given an integer N, outputs the number of years we have to get to N A.D. or how many years it has been since N A.D, as a string or int. For example, given 2014, the program ...