# All Questions

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### The fourth power (Juzuk)

In 1939 Juzuk described a way to generate the fourth powers of natural numbers. Group the natural numbers like this: ...
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/...
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: ...
636 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 ...
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 ...
476 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 the same. For ...
11k 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 ...
787 views

### Circles of text

Find a way to make circles of a given radius using characters in a console. Please specify the font name and size. Also, please provide at least one example of the output. For example: Input: ...
7k 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 : ...
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 ...
625 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 / ...
2k views

### Detect rotated strings

Read two strings from stdin. Output Yes if one string is a rotated version of the other. Otherwise output ...
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) ...
559 views

### Obtain a number from 4 numbers using any combination of mathematical operations [closed]

Given 4 numbers n1, n2, n3, n4, and a goal n5, obtain n5 using n1 through n4 combined with any operations. Eg. Given four numbers 2,3,4,5 and the goal as 8, output (one of many) is ...
801 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 ...
575 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). ...
11k 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 ...
3k views

### Chessboard pattern

Input: a positive number, smaller then 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 letter '...
362 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.
576 views

### Break the broken hash [closed]

Some time ago, I found this unused hash function (written in Java) in our codebase: ...
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 (...
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 ...
298 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: ...
335 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). ...
3k 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 ...
811 views

### Break the broken cipher

I have designed a simple random generator that cycles two numbers in a chaotic way using a multiply and modulus method. It works great for that. If I were to use it as a cipher generator it would ...
887 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 ...
2k 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 ...
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 ...
686 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]. ...
7k views

### Sum of positive integers. [closed]

Problem: Given a set of integers, find the sum of all positive integers in it. Input: t – number of test cases [t < 1000] On each of next t lines, an integer N [-1000 ≤ N ≤ 1000] Output The ...
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 the function to ...
968 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. ...
988 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. ...
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 ...
1k views

### Implement PCRE in your language.

Note: After trying this myself, I soon realized what a mistake this was. Therfore, I am modifying the rules a bit. The minimum required functionality: Character classes (...
2k views

### Guess the number

Description Create a fully working "Guess the number" game. The game is played by two players as follows: player one chooses a number (A) between 1 and N player two tries to guess A choosing a ...
396 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. ...
7k views

### What's my name? Produce the name of the language indirectly [closed]

Produce only the name of a programming language using only the facilities of the language itself. The name of the language can only be invoked indirectly, i.e., from non custom environment variables, ...
5k views

### Add a feature to a programming language [closed]

Your task is to tack on a feature to a programming language, either by implementing a very clever library, or by processing the input text and/or tweaking the compilation process. Ideas: Add PHP-...
379 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: ...
370 views

### Mixed up output [duplicate]

Write a function or program that outputs the following lines <input> time: ...
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 ...
433 views

### Golfed fixed point combinator

Write a fixed point combinator in as few characters as possible, in the language of your choice. free form (i.e., whatever's shortest): whole program, actual function, code snippet you may not use ...
1k views

### How would you count score in a Scrabble® game? [closed]

Let's say that we are programming a game that lets you play Scrabble®. We have a board with tiles placed on it, and empty cells are either normal or have multiplier properties (double or triple the ...
2k views

### Noughts and Crosses (aka Tic-Tac-Toe)

Write a Notes and Crosses application. User interface is optional. You can output the computers move in text: eg 1x1 (meaning ...
6k views

### Reinvent the For loop [closed]

For loops are used extensively in many languages, but what would you do if no languages supported them? Create a way to execute a basic ...
2k views

### Run-Length Encoding [duplicate]

Write a program uses run-length encoding to shorten a list of non-negative integers it has to read in. You can assume the non-negative integers can fit in 32bit signed integers. Input Format The ...