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# Questions tagged [code-golf]

Code-golf is a competition to solve a particular problem in the fewest bytes of source code.

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2answers
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### What is a good way to deal with tasks that require arrays using Haskell?

Often a task requires real arrays. Take for instance the task to implement Befunge or ><>. I tried to use the Array module for this, but it's really cumbersome, ...
31answers
2k views

### Mathematical Combination

Write a program that takes an input such as: n,k which then computes: $$\binom n k = \frac {n!} {k!(n-k)!}$$ and then prints the result. A numerical example: ...
5answers
1k views

### Polynomial Interpolation

Write a program that performs Polynomial Interpolation using true arbitrary precision rational numbers. The input looks like this: f(1) = 2/3 f(2) = 4/5 f(3) = 6/7 ... You may assume that there's ...
8answers
800 views

### Finding maximum paths

Given a square of positive, natural numbers write a program find a horizontal and a vertical path with the sum of numbers along them being maximal. A horizontal path goes from the first column to the ...
15answers
3k views

### The Time Traveler

The shortest code to generate the correct times on the clocks wins. You are a seasoned time traveler and have been known to stop at many planets during your journies. Each planet rotates at a ...
12answers
1k views

### An Old Irish Blessing

I don't know who coined these words, and I'm not Irish, but I give you an Irish blessing: ...
5answers
704 views

### A subset of Verbal arithmetic

Implement a verbal arithmetic solver of several same sequence of numbers added together: ...
7answers
3k views

### Decompose a permutation into cycles

There is a well-known theorem that any permutation can be decomposed into a set of cycles. Your job is to write the shortest possible program to do so. Input: Two lines. The first contains a ...
9answers
2k views

### Forking Factorials

This golf requires a factorial calculation be split up among multiple threads or processes. Some languages make this easier to coordinate than others, so it is lang agnostic. Ungolfed example code is ...
5answers
2k views

### Visualize long division with ASCII art

Write a program that visualizes long division with ASCII art. Input consists of two integers, a numerator and a denominator, using the input format of your choice. Examples: 1234 ÷ 56: <...
2answers
979 views

### Floating point addition, without floats!

Your task is to write a program, in any language, that adds two floating point numbers together WITHOUT using any fractional or floating point maths. Integer maths is allowed. Format The format for ...
15answers
2k views

### Langton's ant ASCII art.

Draw the path of Langton's ant. Description Squares on a plane are colored variously either black or white. We arbitrarily identify one square as the "ant". The ant can travel in any of the four ...
9answers
4k views

### Interpret ><> (Fish)

While ><> is not a popular language, it can be good for golfing and has been used on this website. It was inspired by Befunge and has some similarities in its instructions. Required Commands: <...
1answer
5k views

### Build a simple proxy

Make the shortest proxy server. Input/Output Specifications Client: Input: a port number (32-bit integer) (,) or (space) a url (see test cases) Output: html source of the url Server: Input: port ...
13answers
2k views

### Compute the first N digits of e

Challenge Write a program to compute the the first N (<= 10^3) digits of e. Your program should take an integer N as input. Input: 100 Output: ...
20answers
1k views

### Uptime Progress Bar

Write a program which parses the output of uptime and generates an anatomically suggestive progress bar (as shown) with a length equal to the current uptime in days:...
4answers
414 views

### The fourth power (Juzuk)

In 1939 Juzuk described a way to generate the fourth powers of natural numbers. Group the natural numbers like this: ...
101answers
13k views

### Hello World 0.0!

source: Dilbert, September 8, 1992 I'm hoping to add a new twist on the classic "Hello World!" program. Code a program that outputs Hello World! without: String/...
14answers
2k views

### Draw a Suanpan abacus

Write the shortest program that takes a single integer as input and prints out a Suanpan abacus Testcases Input: 314159 Output: ...
2answers
650 views

### Simple Geometric problem

This problem (see below) has been given as a High School Programming League code golf challenge. The shortest codes submitted during the contest were: 177 bytes in Ruby, 212 bytes in Python 2.5, 265 ...
9answers
3k views

### Calculate digits of Pi

This is a somewhat different task. Calculate 1024 hexadecimal digits of π, beginning at the 1024th hexadecimal place. Formally: Your program should complete in less then 1 minute and produce the ...
4answers
603 views

### Permutation group operation

There is a well-known bijection between the permutations of $n$ elements and the numbers $0$ to $n!-1$ such that the lexicographic ordering of the permutations and the corresponding numbers is ...
36answers
12k views

### Determine if 4 points form a square

Write a function that takes 4 points on the plane as input and returns true iff the 4 points form a square. The points will have integral coordinates with absolute values < 1000. You may use any ...
78answers
8k views

### Answer to life, the universe, and everything

Task Given a String as input, your task is to output 42 only if the input String happens to be exactly the following : ...
8answers
1k views

### Quine Challenge I

Challenge In this task you have to write a program that will take input an integer N (-1e9 <= N < 0 && 0 < N <= +1e9), then compute T = (abs(N) % M+1),if N is positive ...
2answers
665 views

### GolfScript - The missing function

The GolfScript language has one serious lack, no float or fixed point handling. Remedy this by creating a function F for converting an integer number, given as a string, to a string representing 1 / ...
46answers
2k views

### Detect rotated strings

Read two strings from stdin. Output Yes if one string is a rotated version of the other. Otherwise output ...
1answer
3k views

### Solve the 8 Puzzle

The 8 Puzzle is the smaller variant of the 15Puzzle (or the Sliding puzzle). You have a 3x3 grid which is filled with numbers from 0-8 (0 denotes the blank tile) ...
8answers
808 views

### Code Golf: Number of paths!

Challenge Consider a square matrix of order N(N rows and N columns). At each step you can move one step to the right or one step to the top. How many possibilities are to reach (N,N) from ...
2answers
636 views

### Turn 2D boolean array into (rectilinear) polygons

Challenge Write a program which, given a 2-dimensional boolean array (equivalently, a monochromatic bitmap), outputs a series of polygons that describe the outline of the region that is “true” (1). ...
138answers
12k views

### Determine whether strings are anagrams

Challenge Given two strings, work out if they both have exactly the same characters in them. Example Input word, wrdo This returns true because they are the ...
54answers
4k views

### Chessboard pattern

Input: a positive number $n$, smaller than $80$, from stdin or as a command-line argument. Output: A square chessboard pattern, the size of the input number. The dark fields are represented by the ...
1answer
366 views

### Check printer - Convert to English text from the input value.

Check printer function (or subroutine) - Convert to English text from the input value. 12.34 -> "twelve dollars and thirty four cents". For the range .01 to 9999.99 assuming valid input.
5answers
2k views

### ASCII art Bresenham line drawing

Write the shortest possible program that draws a Bresenham line in ASCII art. Your program should take two integers x and y (...
12answers
2k views

### Hitting 495 (Kaprekar) [duplicate]

Input: A three digit number from stdin or as an argument not all digits are the same may start with one or two zero's Process Order the input-digits ascending and descending to form two new ...
5answers
342 views

### Rotate Cartesian coordinates.

Write a program rotates some Cartesian coordinates through an angle about the origin (0.0,0.0). The angle and coordinates will be read from a single line of stdin in the following format: ...
3answers
339 views

### Shorten this code while fixing a major bug [closed]

I found the code below today after much hair pulling. Shorten it down (code golf) and fix the bug that I found (bonus). ...
7answers
4k views

### Implement Shamir's Secret Sharing reconstruction

Shamir's secret sharing scheme is a simple way of protecting a secret by splitting it into several parts needed to reconstruct it. Your task is to implement Shamir's Secret Sharing reconstruction ...
20answers
930 views

### Calculate probability of getting half as many heads as coin tosses.

Write a program that, given a small positive even integer from standard input, calculates the probability that flipping that many coins will result in half as many heads. For example, given 2 coins ...
15answers
3k views

### Draw a BCD Binary clock

Create a BCD binary clock in ASCII. As implied, it shall display time in six columns of dots: (source: Wikimedia Commons) Each column is a binary-coded digit, reading hours, minutes and seconds ...
8answers
2k views

### Output a playable crossword grid

Write a program to produce a file containing a crossword grid that the user can print out and work the puzzle on. Input A filename representing a crossword grid file and optionally a second ...
6answers
692 views

### Write a program to perform set operations.

Your task is to write a program to perform set operations. The operations and arguments are taken from command line in the format program operation [argument]. ...
16answers
1k views

### Numbers, Sums, Products

Given a 20×20 grid of non-negative integers, find a 3×3 sub-grid where the product of the sums of the individual lines hits the maximum. Spoken in formulas: Given the 3×3 sub-grid \mathfrak{U} = \...
14answers
1k views

### Percentage of work days in a month

Given a year and a month, find out the percentage of work days in said month. Work days are Monday through Friday with no regard to holidays or other special things. The Gregorian calendar is used. ...
15answers
1k views

### Make a number palindrome

Write a function that takes a number as an argument and makes it a palindrome by appending minimum number of digits. The number will be at max of 100 digits. ...
19answers
4k views

### My Word can beat up your Word

PROBLEM Given two words, find the winner in a digital root battle. Define the digital root of a word this way: Each letter of the alphabet is assigned a number: A = 1, B = 2, C = 3, ..., Z = 26 ...
7answers
431 views

### Shortest Port Scanner

Write the shortest program that will attempt to connect to open ports on a remote computer and check if they are open. (It's called a Port Scanner) Take input from command line arguments. ...
2answers
386 views

### Implement cdbmake

Write the shortest program to build a cdb database, using the following syntax for input: +klen,dlen:key->data followed by a newline. Example: ...
9answers
383 views

### Mixed up output [duplicate]

Write a function or program that outputs the following lines <input> time: ...
5answers
2k views

### The Tic Tac Toe Dictionary

A TicTacToe game can be represented by a string denoting the sequence of positions as the players make their move. 0 1 2 3 4 5 6 7 8 Assume ...