All Questions
13,911
questions
13
votes
10
answers
1k
views
Forecast the weather
Write the shortest program to forecast the weather for the next 7 days
The input (from stdin) is the weekday and the season
The output (to stdout) is seven lines weekday and the temperature in ...
- 15.1k
30
votes
47
answers
3k
views
Implement Bogosort
Is solving Sudoku too hard? Even the brute force version? Here's a coding exercise that's a little easier. I hope. :-P
Write the shortest function to implement bogosort. In specific, your function ...
- 4,917
25
votes
13
answers
5k
views
Implement a Brute Force Sudoku Solver
Implement the shortest Sudoku solver using guessing. Since I have received a few request I have added this as an alternative question for those wishing to implement a brute force sudoku solver.
...
- 717
9
votes
1
answer
2k
views
Build an engine for a maze game
This is a follow up of Print a maze question. If you like this question, please add more maze generation algorithms ;).
For this task you'll have to implement a game engine for one player who must ...
- 6,066
18
votes
52
answers
2k
views
IPv4 Integer Conversion Function
Write the shortest function to convert an IP address into it's integer representation and output it as an integer.
To change an IPv4 address to it's integer representation, the following calculation ...
- 301
78
votes
53
answers
35k
views
Tips for golfing in Ruby
What general tips can you give for golfing in Ruby?
I'm looking for ideas that can be applied to code golf problems in general that are specific to Ruby. (For example, "Remove comments" would not be ...
- 1,257
28
votes
4
answers
3k
views
34
votes
55
answers
7k
views
Calculate ISBN-13 check digit
Write a function which, given the first 12 digits of an ISBN-13 code, will calculate the entire ISBN via calculating and appending an appropriate check digit.
Your function's input is a string ...
- 6,442
12
votes
8
answers
6k
views
Binary tree encoding [closed]
Let's suppose you have a complete binary tree (i.e. each internal node has exactly two non empty descendants). Each node contains a nonzero integer. You are given the task of encoding and decoding the ...
- 6,066
8
votes
4
answers
580
views
Binary search ("bisect") tool
Implement the binary search algorithm as used to identify the source code revision that breaks a computer software program. Your tool should take two arguments specifying the earliest and latest ...
- 5,577
9
votes
10
answers
3k
views
Crossword numbering
Produce a program to correctly number a crossword grid.
Input
The input will be the name of a file representing the crossword
grid. The input filename may be passed as an argument, on the
standard ...
136
votes
144
answers
44k
views
Obfuscated Hello World
Create the shortest possible obfuscated program that displays the text "Hello World".
In order to be considered an obfuscated program, it must meet at least two of the following requirements:
Does ...
- 6,442
9
votes
3
answers
908
views
Project Euler Problem 12: optimize memory usage
I am referring to Project Euler #12. Write the solution in any language you want, but consume the least amount of memory while executing. Running time is not measure in this case.
The sequence of ...
- 283
18
votes
2
answers
809
views
Quine that takes as input the name of a language and outputs the same thing implemented in the input language
From Quine central:
Write a quine that takes as input the name of a language and outputs the same thing implemented in the input language.
The source article has something you can work from, but as ...
- 12.5k
17
votes
44
answers
6k
views
Shortest Floor Function
Your task is to implement a floor function in as few bytes as possible.
A floor function is a function that takes a real number and returns the largest integer less than or equal to the input.
Your ...
- 732
50
votes
11
answers
16k
views
Write an interpreter for the untyped lambda calculus
The challenge is to write an interpreter for the untyped lambda calculus in as few characters as possible. We define the untyped lambda calculus as follows:
Syntax
There are the following three ...
- 1,839
31
votes
19
answers
13k
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 ...
- 5,577
6
votes
1
answer
2k
views
Nokia mystery puzzle [closed]
A friend sent me this puzzle. I'm pretty sure solving it will require some programming. Can anyone crack it? The original is here in case of encoding issues in the past below.
...
- 12.5k
11
votes
2
answers
5k
views
Decryption by pattern analysis
You are given an encrypted string, encrypted using a very simple substitution cipher.
Problem
You do not know what the cipher is but you do know the ciphertext is English and that the most frequent ...
- 3,318
27
votes
19
answers
9k
views
Print 1 to 1000 in C++ without semi-colons
Following this popular question, present your solution which prints the numbers 1 to 1000 (all of them, not the string "1 to 1000" verbatim or something funny) in C++ without using any semi-colons. ...
- 12.5k
19
votes
5
answers
5k
views
Print a random maze
Write a program that generates and prints a random maze using the algorithm of your choice. The maze should be different for multiple runs of the program. Height and width are given as command line ...
- 6,066
67
votes
140
answers
11k
views
Reverse stdin and place on stdout
Requirements:
Take an input on stdin including new lines / carriage returns of unlimited length (only bounded by system memory; that is, there is no inherent limit in the program.)
Output the reverse ...
- 3,318
49
votes
48
answers
10k
views
Reverse Polish notation
You must evaluate a string written in Reverse Polish notation and output the result.
The program must accept an input and return the output. For programming languages that do not have functions to ...
user11
18
votes
12
answers
880
views
Compute modular inverse
Given two positive numbers \$x\$ and \$n\$ with \$x<2^n\$, write the shortest possible function to compute \$x^{-1} \mod 2^n\$. In other words, find \$y\$ such that \$xy=1 \mod 2^n\$.
Your ...
- 20.8k
17
votes
2
answers
1k
views
Slot Machine Hacker
Problem: Slot Machine Hacker from Facebook Hacker Cup 2011 Round 1B
Goal: Shortest code in your favourite language using stdin/stdout. You cannot assume ...
- 12.5k
15
votes
4
answers
1k
views
Freely available books for code golfing? [closed]
Can you recommend any freely available books about code golfing in general and especially in Java and C++?
50
votes
49
answers
7k
views
Tips for golfing in PowerShell
What general tips do you have for golfing in Windows PowerShell? I'm looking for ideas that can be applied to code golf problems in general that are at least somewhat specific to PowerShell (e.g. "...
- 12.9k
35
votes
14
answers
24k
views
Drawing a cube in ASCII art
Task description:
Draw a cube in ASCII art in roughly a cabinet projection.
Monospaced fonts often have characters that are about twice as high as they are wide. ...
- 12.9k
6
votes
33
answers
3k
views
Print largest integer you can with the fewest characters [closed]
Find a way to output a large integer with few characters. Solutions will be scored based on the magnitude of the number and shortness of code.
EDIT: Let's impose a time limit of a minute on sensible ...
- 12.5k
27
votes
37
answers
3k
views
Finding "sub-palindromes".
The shortest code that finds all unique "sub-palindromes" of a string, that is: any substring with length > 1 that is a palindrome.
eg.1
...
- 5,452
75
votes
59
answers
20k
views
Tips for code-golfing in C#
What general tips do you have for golfing in C#? I'm looking for ideas that can be applied to code golf problems in general that are at least somewhat specific to C# (e.g. "remove comments" is not an ...
- 1,863
38
votes
55
answers
4k
views
196 algorithm code golf
Write a short program for 196-algorithm.
The algorithm starts from an integer, then adds its reverse to it until a palindrome is reached.
e.g.
...
- 5,452
13
votes
1
answer
1k
views
Shortest path in a graph
Write a program to take a graph (from either standard input or a file, your choice) and find a shortest path in the graph.
Graphs are specified using the following format:
...
- 20.8k
6
votes
3
answers
431
views
Compress programs
Write a program/script that decompresses and passes any compressed data appended at the end of the binary/file as standard input to a program specified as arguments.
...
- 6,066
11
votes
1
answer
732
views
Write a compressing util for gzip files
The task of this challenge is as following:
Write a program that reads a file of reasonable size (let's say <16 MB) from stdin or anywhere else (however you like, but must not be hardcoded), and ...
- 10.1k
62
votes
30
answers
19k
views
Tips for golfing in C++
What general tips do you have for golfing in C++?
I'm looking for ideas that can be applied to code golf problems in general that are at least somewhat specific to C++ (e.g. "remove comments" is not ...
- 12.5k
37
votes
26
answers
33k
views
Morse code translator
Write the shortest program to transform the standard input into Morse code. Characters not in the table should be printed as they are.
- 6,066
-2
votes
1
answer
5k
views
Poisson random number generator [closed]
What is the shortest function (implemented in C) that will return a random draw from a Poisson distribution (given the mean or λ parameter)?
...
- 732
11
votes
2
answers
3k
views
Test if a given number is a Vampire Number [duplicate]
EDIT: In the interest of increasing the complexity, i've added more to the challenge.
In mathematics, a vampire number (or
true vampire number) is a composite
natural number v, with an even ...
- 2,208
4
votes
5
answers
935
views
Tree traversal. [closed]
Write the shortest code that traverses a tree, breadth-first.
Input
any way you like
Output
a list of "names" of the nodes in correct order.
- 5,452
36
votes
61
answers
5k
views
Sum of primes between given range
Write the shortest code for finding the sum of primes between \$a\$ and \$b\$ (inclusive).
Input
\$a\$ and \$b\$ can be taken from command line or stdin (space seperated)
Assume \$1 \le a \le b \le ...
- 2,208
3
votes
3
answers
266
views
Sharing Inherited Land [closed]
You and your brother have inherited a rectanglar block of land. This block of land's corners are read in from stdio as TLX,TLY,TRX,TRY,BLX,BLY,BRX,BRY (all decimal ...
- 1,007
48
votes
41
answers
17k
views
Obfuscated FizzBuzz Golf [closed]
Create the shortest possible obfuscated FizzBuzz implementation.
To be considered obfuscated, it should satisfy at least one of the following:
Does not contain any of the words "Fizz", "Buzz", or "...
- 1,199
149
votes
330
answers
42k
views
Fibonacci function or sequence
The Fibonacci sequence is a sequence of numbers, where every number in the sequence is the sum of the two numbers preceding it. The first two numbers in the sequence are both 1. Here are the first ...
- 4,917
147
votes
78
answers
25k
views
Interpret brainfuck
Write the shortest program in your favourite language to interpret a brainfuck program. The program is read from a file. Input and output are standard input and standard output.
Cell size: 8bit ...
- 6,066
24
votes
38
answers
4k
views
Reimplementing square root [duplicate]
Define a function, s, which takes a number and returns the square root.
No use of library functions, such as Java's Math.sqrt() or PHP's built in sqrt(), allowed.
- 1,145
242
votes
450
answers
63k
views
Golf you a quine for great good!
Using your language of choice, golf a quine.
A quine is a non-empty computer program which takes no input and produces a copy of its own source code as its only output.
No cheating -- that means ...
- 2,697
326
votes
177
answers
139k
views
Tips for golfing in Python
What general tips do you have for golfing in Python? I'm looking for ideas which can be applied to code-golf problems and which are also at least somewhat specific to Python (e.g. "remove comments" is ...
- 12.5k
14
votes
5
answers
765
views
Fast Topswops calculation [closed]
From AZSPCS:
Suppose you have a deck containing n cards. Each card contains a number from 1 to n, and each number appears on exactly one card. You look at the number on the top card -- let's says it'...
- 6,066
11
votes
4
answers
2k
views
Fast line drawing algorithm
The task is to find a way to draw a horizontal line in an array of 16-bit integers.
We're assuming a 256x192 pixel array with 16 pixels per word. A line is a contiguous run of set (1) bits. Lines ...
- 3,318