# Questions tagged [code-golf]

Code-golf is a competition to solve a particular problem in the fewest bytes of source code. If you want to score by characters instead of bytes, please state this explicitly in the challenge. If source code length is not the primary scoring criterion, consider using another tag instead.

8,816 questions
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### BF Last binary digit [duplicate]

Task Your task is to write as short as possible program preferably in Brainf**k which determines the last digit of given number after it's conversion from decimal to binary system. Input An integer ...
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### Terrain Reachability

Turn-based tactics games like Advance Wars, Wargroove, and Fire Emblem are made up of a square grid of varying terrain with units of differing movement classes requiring different costs for each ...
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### Return the Closest Prime Number

Challenge This is a simple one: Given a positive integer up to 1,000,000, return the closest prime number. If the number itself is prime, then you should return that number; if there are two primes ...
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Introduction: I saw there was only one other badminton related challenge right now. Since I play badminton myself (for the past 13 years now), I figured I'd add some badminton-related challenges. ...
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### Implement the Thanos sorting algorithm

The sorting algorithm goes like this: While the list is not sorted, snap half of all items (remove them from the list). Continue until the list is sorted or only one item remains (which is sorted by ...
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### Lay out the Carpet

Inspired by this SO question. Challenge: Input: A string $s$ A character $c$ Output: Create a diamond-square ASCII art of the string in all four directions, with the first character of the ...
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### Next number with k fives

Challenge: Your program will take two integers n and k as input, and output the smallest integer greater than (but not equal to)...
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### Counting the number of restricted forests on the Möbius ladder of length n

OEIS sequence A020872 counts the number of restricted forests on the Möbius ladder Mn. The Challenge The challenge is to write a program that takes an integer as an input ...
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### Is there a smaller tautogram checker? [closed]

I got into code-golfing recently and tried to write the smallest tautogram checker. A tautogram is a sentence in which all words start with the same letter, for example: Flowers flourish from France. ...
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### Greatest common substring

Create a program or function which takes a list of strings as input, and outputs the longest string that is a substring of all input strings. If there are several substrings of equal length, and no ...
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### Draw these shapes [closed]

Given: a width, a height, and a set of sets of points. Output: An image where each set of points is connected and colored in (like a shape). Each shape must be a different color from all of the other ...
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### Sub-pixel Zooming

Your task is to take a 24 BPP sRGB image and output the same image upscaled 3x into red, green, and blue subpixels. The resulting image will be made entirely of pure black, red, green, and blue pixels....
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### Nearest hamming cycle period in MD5

This riddle was inspired by that thread. Consider that you are super-hacker and try to break MD5 hashing algorithm by looking for a hash collisions for a given hash string which your friend gave to ...
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### Calculating total slots

Given a list of jobs, which must be done in order, with each taking a slot to do, how long will it take to perform them all if after doing a job the same job cannot be done for the next two slots (...
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### Japanese Multiplication [duplicate]

There's a visual method for multiplication that is taught to Japanese schoolchildren [citation needed] that uses lines and crossings to get the answer. Image Source Your task is to implement this in ...
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### Multiplicative persistence

Multiplicative Persistence Multiply all the digits in a number Repeat until you have a single digit left As explained by Numberphile: Numberphile "What's special about 277777788888899?" Numberphile ...
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### The Digit Triangles

Challenge: Input: A positive integer $n$ Output: Create a list in the range $[1,n]$, and join it together to a string (i.e. $n=13$ would be the string ...
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### Morse sudo-ku-de

Hehe, see what I did with the title? Anyways... Your job is to create a sudoku solver that accepts input in Morse code and creates output in Morse code. Here's the Morse code numbers for reference: <...
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### Make a Bowl of Alphabet Soup

This is what we'll call a bowl of alphabet soup - a roughly circular ascii-art shape with the 26 uppercase English letters (A-Z) arranged clockwise to form the perimeter: ...
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### New Order #2: Turn My Way

Introduction (may be ignored) Putting all positive numbers in its regular order (1, 2, 3, ...) is a bit boring, isn't it? So here is a series of challenges around permutations (reshuffelings) of all ...
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### Offset in split text content

You will be given an ASCII text. This text may have zero, one or many appearances of a split a character (let's assume it will be the space character ) You will ...
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### Output visual diagram of picture

Write a program that inputs the dimensions of a painting, the matting width, and the frame width for a framed portrait. The program should output a diagram using the symbol ...
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### Is this Pascal's Matrix?

In Pascal's triangle each number is the sum of the two numbers directly above it, treating empty spots as zero: By rotating the triangle, we can cut out square matrices of varying sizes and rotations ...
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### Convert ASCII art numbers to integers

Inspired by this game Challenge: Given an ASCII art string representing a number, output that number. Example: ...
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### Would this string work as string?

Write a program that takes a single line string that you can assume will only contain the characters /\_‾. (That's forward and backward slash, underline and ...
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### Find all diagonal counts in only one direction [closed]

If I need to get the number of diagonal squares in all directions: I do the following formula 2 N − 2 − |x − y| − |x + y − N − 1| The above example has 13 and ...
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### Gotta Collect 'Em All

Your task here will be to write a very dumb AI capable of fetching all treasures on a map. Map The map is defined as follow: (artist-mode™-powered) Basic case: <...
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### Which were the latest 13 consecutive years with the most friday 13. in total? [closed]

Shortest program wins, of course.
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### Print last inputted byte

Challenge You have one string of input bytes, output the last byte in it. Rules Your submission may be a program or function outputting the last byte in the input which is either a string, stdin ...
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### Sort a list of Numbers as letters [closed]

So, you have a random list (random meaning it doesn't matter what order it is in) of numbers with a length of n, where n is a positive integer smaller than 1000 and ...
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### Pi Day: Determine if a list of words is correct Pilish

Background Though this is a bit late for Pi Day, I saw an article about Pilish and thought it would make a great challenge. Pilish is created by using a sequence of words where each word's length ...
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### Print a physical multiplication table

Rectangles have this nice property - an $n \times m$ rectangle consists of exactly $n \times m$ characters! A.. more interesting property is that the rectangles can be aligned nicely in a ...
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### Pólya urn flip and roll

Problem statement Pólya is playing about with his urn again and he wants you to help him calculate some probabilities. In this urn experiment Pólya has an urn which initially contains 1 red and 1 ...
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### It's a yearly task, alright

Given a number 1≤n≤365, output the nth day of the year in "Day-numberth Month" format. For example, given 1, you should output "1st January", without "of". The Gregorian calendar will be used and the ...
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### Make a transparent 448*448 image

This is a simple challenge. The task is to write code that outputs a 448*448 square image with 100% transparency. The output should follow the standard image rules.
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### Am I not good enough for you?

Background: The current Perfect Numbers challenge is rather flawed and complicated, since it asks you to output in a complex format involving the factors of the number. This is a purely decision-...
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### They call me Inspector Morse

Your mission, should you choose to accept it, is to decide whether a given input string is Dot-heavy, or Dash-heavy. A string is dot-heavy when its morse representation contains more dots than dashes....
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+100

Challenge: Input: A list of distinct positive integers within the range $[1, \text{list-size}]$. Output: An integer: the amount of times the list is riffle-shuffled. For a list, this means the ...
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### New Order #1: How does this feel?

Introduction Putting all positive numbers in its regular order (1, 2, 3, ...) is a bit boring, isn't it? So here is a series of challenges around permutations (reshuffelings) of all positive numbers. ...
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### Shift the weekday!

Employers love to see their employees working hard, while the employees would love to work less, especially those with a monthly rather than hourly payment. The laziest of employees are thinking ...
541 views

### Black Hole challenge from codewars

I came across this challenge from codewars. I wish to know how to solve this problem. The problem description is given below. Its elements are in range[1..n^2]. The matrix is filled by rings, from ...
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### Cycles on the torus

Challenge This challenge will have you write a program that takes in two integers n and m and outputs the number non-...
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### It's Halloween again!

Problem Description We all love a Twix (because it is the best candy), but this is the kids' first Halloween --- we gotta grab at least one of each type of candy for them. Each Halloween all the ...
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### Is it a Cyclops number? “Nobody” knows!

Task: Given an integer input, figure out whether or not it is a Cyclops Number. What is a Cyclops number, you may ask? Well, it's a number whose binary representation only has one ...
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### The (Easy) Road to Code

Input: An integer $n$, which is guaranteed to be $\ge3$. An integer $d$, which is one of $[-1,0,1]$. Output: A road of size $n$, which will be in a north-west direction if $d=-1$; a ...
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### Sum integers in a string

Input A string. Output The sum of all integers in the line. Constraints 1≤Length of line≤500 Sample test Case Input the 5is 108 seCONd4 a Output ...
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### Deal the cards to the players

Tonight is card game night! You are the dealer and your task is to write a program to deal the cards to the players. Given an array of cards and the number of players, you need to split the array of ...
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### Is it a valid penalty shoot-out prefix?

In association football (also known as soccer), a penalty shoot-out is the second tie-breaker measure that may be used in a match which can't end in a tie, after extra time (i.e. association football ...