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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43
votes
55answers
10k views

I reverse the source code, you negate the output!

Your task, if you wish to accept it, is to write a program that outputs a non-zero number(can be integer or float). The tricky part is that if I reverse your source code, the output must be the ...
35
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46answers
5k views

Generate Monday Numbers

Monday numbers, as defined by Gamow in this question over on Puzzling, are positive integers N with the following three properties: The decimal representation of N does not contain the digit 0 The ...
29
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29answers
4k views

Render “Digital Clock Style” Numbers

Write the shortest program which will take a string of numbers (of up to at least 20 length) as input, and display the output using the standard digital clock style numbers. For instance for input 81,...
27
votes
15answers
11k views

Twinkle Twinkle Little Star

Write a program to play the popular English nursery rhyme. (This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. Attribution: Helix84 at the English language ...
52
votes
9answers
4k views

Unfolding the Hexagony source code

Introduction If you're not familiar with Hexagony, it's an esoteric language created by Martin Büttner. The thing is that this language accepts multiple forms for the program. The following programs ...
25
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11answers
1k views

Tips for golfing in Swift

What are some tips for code-golfing in Swift? Its focus on safety seems to make it difficult to golf in, but that makes little tips and even more useful. Are there any features in Swift that may help ...
19
votes
13answers
635 views

Tips for golfing in dc

What general tips do you have for golfing in dc? dc is a calculator utility for UNIX/Linux that predates the C language. I am interested in how to make my dc programs (calculations?) shorter. I'm ...
18
votes
10answers
2k views

stupid restrictions and desert

So, you were sitting at your desk, golfing a program to calculate the first 20 digits of pi, and along comes your boss and throws your apple IIe out the window. You are now working on a new project ...
46
votes
10answers
2k views

Zigzagify a String

Write a program (or function) that takes in a non-empty string of any printable ASCII characters. Print (or return) a zigzagging chain of the characters in the string with every neighboring pair of ...
35
votes
48answers
3k views

Boustrophedonise

Related but very different. A boustrophedon is a text where every other line of writing is flipped or reversed, with reversed letters. In this challenge, we will just reverse every other line, but ...
34
votes
22answers
7k views

XOR multiplication

You goal is to implement the operation of XOR (carryless) multiplication, defined below, in as few bytes as possible. If we think of bitwise XOR (^) as binary ...
33
votes
36answers
4k views

Is it Christmas?

Challenge Given that Christmas is: December Month 12 Day 25 Every year, determine today's date, and whether or not today is Christmas. If it is Christmas, you must print ...
25
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11answers
3k views

Calculate 500 digits of pi

Write a program to calculate the first 500 digits of pi, meeting the rules below: It must be less than 500 characters in length. It cannot include "pi", "math.pi" or similar pi constants, nor may it ...
24
votes
63answers
9k views

Count the number of ones in an unsigned 16-bit integer

Write some statement(s) which will count the number of ones in an unsigned sixteen-bit integer. For example, if the input is 1337, then the result is ...
22
votes
25answers
7k views

Look and say sequence [duplicate]

The look and say sequence is a basic form of run length encoding. The sequence starts with the number 1 and each additional number encodes the number of digits that are repeated before each digit ...
23
votes
21answers
2k views

Different Way Forward

Given a list of integers produce a Forward Difference at a specified order/depth. For the list of integers: (10, 18, -12, 4, 8, -3, -5, 67, 9, 14) The Forward ...
22
votes
9answers
2k views

Name the poker hand

Name the poker hand Given five cards, output the name of the poker hand, which will be one of: ...
19
votes
9answers
616 views

Given an input, move it along the keyboard by N characters

The Challenge: Given any input that can be typed on a keyboard, move the text along by N chars. Here is the QWERTY keyboard to be used. You can ignore the modifier keys (Shift, Caps, Enter, Delete ...
35
votes
45answers
4k views

Generate the Abacaba sequence

This challenge is about printing the abacaba sequence of a specific depth. Here is a diagram of the first 5 sequences (a(N) is the abacaba sequence of depth N, ...
35
votes
28answers
4k views

Find the number in the Champernowne constant

Introduction In base 10, the Champernowne constant is defined by concatenating representations of successive integers. In base 10: 0.1234567891011121314151617... ...
32
votes
55answers
7k views

Binary to decimal converter

Binary to decimal converter As far as I can see, we don't have a simple binary to decimal conversion challenge. Write a program or function that takes a positive binary integer and outputs its ...
21
votes
23answers
3k views

Generate excel column name from index

This one comes from a real life problem. We solved it, of course, but it keeps feeling like it could have be done better, that it's too lengthy and roundabout solution. However none of my colleagues ...
19
votes
14answers
1k views

Discrete Convolution or Polynomial Multiplication

Given two non empty lists of integers, your submission should calculate and return the discrete convolution of the two. Interestingly, if you consider the list elements as coefficients of polynomials, ...
18
votes
2answers
689 views

Each step of the Levenshtein distance

In this challenge you will write a program that takes two newline-separated strings, s1 (the first line) and s2 (the second line), as input (STDIN or closest). You can assume that the length of s1 ...
12
votes
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 ...
11
votes
10answers
2k views

Split string into n pieces (or pieces of length n)

The Challenge In this challenge you have to do two different (but related) tasks depending of the order of the input. Your program will recieve a string s and an ...
10
votes
5answers
2k views

Implement t9-like functionality

Your challenge today is to implement a t9-like functionality. You will implement a function that will only have 2 parameters. You will receive 1 phone number in a string and the content of a text ...
6
votes
7answers
594 views

Determine the position of a non-negative number in the infinite spiral

Definition The infinite spiral used in this question has 0 on the position (0,0), and continues like this: ...
21
votes
8answers
2k views

crossed out 44 is still regular 44 ;(

Introduction On March 24th, 2015 @isaacg golfed his Pyth answer from 44 to 42 bytes. Since a crossed out 44 (44) looks a lot like a regular 44, @Optimizer made the following comment: striked out ...
17
votes
24answers
9k views

12 Days of Christmas Lyrics

I thought this would be a fun challenge for everyone and I'm curious to see the solutions people come up with. Print the "12 Days Of Christmas" lyrics ...
15
votes
97answers
6k views

Turn an integer n into a list containing it n times

Given an integer n as input, return a list containing n, repeated n times. For example, the ...
11
votes
19answers
904 views

Return each number from a group of numbers

The challenge The program must return all numbers included into a group (comma and hyphen separated sequence) of numbers. Rules s is the sequence string; all ...
58
votes
10answers
12k views

Draw the South Korean flag

When I stumbled upon this question I remembered that I had also once seen precise rules for the construction of the South Korean flag. And this is quite a different construction. Source: Wikipedia ...
38
votes
3answers
23k views

Solve Rubik's cube

Write the shortest program that solves Rubik's cube (3*3*3) within a reasonable amount of time and moves (say, max. 5 seconds on your machine and less than 1000 moves). The input is in the format: <...
107
votes
79answers
23k views

Draw the national flag of Iceland

This year's UEFA Euro 2016 is over and besides a couple of negative headlines there has been a very positive surprise as well – the Iceland national football team. Let's draw their national flag. ...
91
votes
48answers
13k views

In Honor of Adam West

Adam West passed away, and I'd like to honor his memory here on PPCG, though I doubt he knew of our existence. While there are many, many different things that this man is known for, none are more ...
82
votes
25answers
7k views

Bake a slice of Pi

Write a program or function that prints or outputs this exact text (consisting of 142 characters): ...
74
votes
39answers
6k views

Stack Exchange Vote Simulator

Write a program or function that takes in a string only containing the characters ^ and v (you can assume there will be no other ...
64
votes
83answers
12k views

Golf all the 16 logic gates with 2 inputs and 1 output!

For example, the gate A and B is a logic gate with 2 inputs and 1 output. There are exactly 16 of them, because: each logic gate takes two inputs, which can be ...
47
votes
15answers
5k views

ASCII Art of the Day #1 - Double Knot

Write a full program or a function that takes a positive integer N as input via STDIN/command line/ARGV or function arguments and prints an ASCII double knot ...
28
votes
28answers
3k views

Bit-Reversal Permutations

Your goal is to create a function or a program to reverse the bits in a range of integers given an integer n. In other words, you want to find the bit-reversal permutation of a range of 2n items, zero-...
59
votes
118answers
14k views

Duck, duck, goose!

Remember the kids game, 'Duck, Duck, Goose'? No? Me neither. The challenge Print the word 'duck' on individual lines an indeterminate amount of times. Print the word 'goose'. Your program ends. The ...
57
votes
56answers
6k views

Print N Squared

Write a program or function that takes in a non-negative integer N from stdin or as a function argument. It must print or return a string of a hollow ASCII-art square whose sides are each made with N ...
49
votes
67answers
10k views

Shortest program that continuously allocates memory

Write a program which runs forever and allocates more and more memory on the heap the longer it runs, at least until you reach the limit of the operating system on the amount of memory that can be ...
76
votes
30answers
12k views

Create an “H” from smaller “H”s

Challenge Create a function or program that, when given an integer size, does the following: If size is equal to 1, output <...
45
votes
11answers
2k views

Run Stackylogic

Stackylogic is a logic-based programming language I made up that take in 0's and 1's for input and outputs a single ...
44
votes
9answers
1k views

Cycling with Rubik's

While idly twisting my Rubik's cube around, my son noticed that it kept going back to the solved state. I'm pretty sure he thought this was some sort of voodoo magic at first, but I explained that if ...
31
votes
22answers
5k views

Golfing ASCII-art

Let's try to golf this piece of ascii-art representing a golfing man: '\ . . |>18>> \ . ' . | O>> ...
62
votes
82answers
11k views

What do you get when you multiply 6 by 9? (42)

I love math. But I can't find a single calculator that can multiply correctly. They seem to get everything right except 6*9 (It's the question to life, the universe, and everything! How could they get ...
44
votes
66answers
6k views

It's Hip to be Square

Challenge So, um, it seems that, while we have plenty of challenges that work with square numbers or numbers of other shapes, we don't have one that simply asks: Given an integer ...

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