# Tagged Questions

This challenge is open to any programming or scripting language.

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### Beer Friday Challenge #1: Dynamic conditional puzzle [closed]

Solve, ((15, 'less_than', 30) == true) Use any language you are comfortable with. The only thing you must not do is mentally substitute the words for the symbols. Here's a link to the gist if you ...
134 views

### How to shorten this J code? (Or write shorter code in another language)

I decided to learn J so that I could better take part in code golfing. Starting it off relatively simple, I tried writing a solution to this problem: Find the sum of all the multiples of 3 or 5 ...
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### What happens when you perform “++” operation on an integer with it's max possible value? [closed]

So, it's a classic but I can't find an answer anywhere. Suppose I've an integer 'x' and int takes 32 bits on this platform. I'm performing the "++" operation in a loop. Something like this: int ...
372 views

### Compute the number of ways how you can express a number as a sum

For a given natural number n, compute the number of ways how one can express n as a sum of positive natural numbers. For example, for n = 1 there is just one way. For n = 4 we have 5 possible ways: 1 ...
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### Shortest common superstring

Given a list of strings s_0, s_1, ..., s_n find the shortest string S that contains each of s_0, s_1, ..., s_n as a substring. Examples: S('LOREM', 'DOLOR', 'SED', 'DO', 'MAGNA', 'AD', ...
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### The number of possible numeric outcomes of parenthesizations of 2^2^…^2

Consider an expression 2^2^...^2 with n operators ^. Operator ^ means exponentiation ("to the power of"). Assume that it has no default assosiativity, so the expression needs to be fully parenthesized ...
202 views

### Avoid duplicate entries using a sign change

This anecdote contains the following intriguing exchange: "Fine, Fred," Avi interrupted. "Then how would you change this to avoid duplicate entries?" "Oh, just change that one there to a negative ...
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### Return the number of digits in any given number

Objective Given any terminating, rational number, return the number of digits the number contains. Do not count zeros if they're the last digits. Examples 0 returns 1 -1 returns 1 6.23 returns 3 ...
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### Write a Polish notation interpreter, then change it to RPN in shortest number of chars

Write a program to convert Polish prefix notation to infix notation, then change it to an RPN-to-infix converter in the shortest number of chars. Your score is 100 minus the number of characters ...
430 views

### Challenge: take ciphered text and decipher, also print out if it was offset to the left or right

Problem: Take input text like this: (all input should be considered strings) Upi djpi;f ytu yu[omh pmr yp yjr ;rgy. And figure out if it was offset left or offset right (on a standard qwerty ...
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### Find the generating function of a sequence [duplicate]

Given a set of space-delimited integers, you've gotta either return a function that can generate that sequence, or return "There isn't any such function". Sample input: "1 11 41 79" - x^3+x^2-1 ...
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### Zebra stripe command output

I have a script: \$ cat ~/zebra.pl #!/bin/perl use Term::ANSIColor; \$Term::ANSIColor::EACHLINE = "\n"; my \$zebra = 1; # Are zebras black with white stripes, or white with black stripes?! my \$black ...
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### (Re)Implementing Tetris

In the spirit of re-implementing classic video games, I would like to invite the community to create their best implementation of Tetris. For reference, a screenshot of the official NES version of ...
2k views

### Shortest code to determine if a string is a palindrome

A palindrome is some string that is spelled the same way both backwards and forwards. For instance, 'Eva, can I stab bats in a cave?' is a palindrome (EVACANISTAB | BATSINACAVE) For this code golf, ...
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### Advanced Code Golf - Disk Operations, and File Allocation

Good Afternoon Golfgeneers. This is reasonably long and detailed question. Given what it was asking, it needed to be. If you have any questions, please ask them. If there is anything that isn't ...
334 views

### Sibling Rivalry

Objective Requirements A main 'parent' file and a 'child' file. The parent file creates a new child file that contains code that must execute after creation. The child file that is created must ...
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### Count characters in lo..ol and print a phrase [duplicate]

Assuming 'lol' with a variavle number of 'o's. Print a the following phrase: What does 1st, 2nd, 3rd, 4th ... 'o' stand for? Examples: lol -> What does 1st 'o' stand for? loooool -> What ...
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### Give the smallest number that has N divisors

Your function takes a natural number and returns the smallest natural number that has exactly that amount of divisors, including itself. Exemples: f(1) = 1 [1] f(2) = 2 [1, 2] f(3) = 4 [1, 2, 4] ...
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### Incrementing Numbers, Over Multiple Sessions

Good Evening Golf Agents, Your mission is on behalf of notorious entertainment giant Eviltronic Arts. As part of their nefarious plan for world enslavement and entertainment, they must sell as many ...
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### Implement DFA/NFA/epsilon-NFA

Write the shortest code that implements a: DFA NFA epsilon-NFA The program should accept as input: a string(that we want to see if is accepted or not) the delta function, represented in ...
1k views

### The world ends in ed

Taken straight from the ACM Winter Programming Contest 2013. You are a person who likes to take things literally. Therefore, for you, the end of The World is ed; the last letters of "The" and "World" ...
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### chess - calculate all legal moves from fen string ignoring castling and en passant

Write the shortest code that calculates all possible (legal) moves of current player from a given FEN string. What is FEN string? (Wikipedia) Shortest code wins, language doesn't matter. Output ...
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### Minimalist web server [duplicate]

The challenge is to make the shortest fully functioning web server possible. You should give fully working code that can serve static pages from a given local directory. The code can be in any free ...
1k 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: ...
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### Find largest prime which is still a prime after digit deletion

Over at http://math.stackexchange.com/questions/33094/deleting-any-digit-yields-a-prime-is-there-a-name-for-this the following question is asked. How many primes are there that remain prime after you ...
447 views

### Print ASCII histogram

The challenge is to give as short code as possible to print an ASCII histogram of a set of data. Input. The number of bins followed by a number of integers representing the data. The data are space ...
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### Pong in the shortest code

The challenge is simple. Give the shortest code possible to reproduce the classic 2-player game of pong http://en.wikipedia.org/wiki/Pong . The level of graphics and functionality should be as close ...
697 views

### Breakout in half an hour

When I was a young teen I had a very boastful friend who claimed he could code up breakout (http://en.wikipedia.org/wiki/Breakout_(video_game)) in half an hour. Half an hour later he had done a great ...
443 views

### Cropping an image succintly

I am constantly frustrated by how complicated it is to write graphical programs that would have been only a few lines of code 20+ years ago. Since the invention of the mouse this has become even ...
321 views

### Simple redstone simulator

Redstone is a material in the game Minecraft, and it is used for many complex contraptions. For this program, you will only need to simulate three items: the redstone wire (noted with R), redstone ...
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### Write ASCII-Art Obfuscated Code, read as, and resulting in: “DFTBA”

The challenge is to write the most elaborate code, embedded in ASCII art that reads and prints "DFTBA". For example, the following reads DFTBA: oooooooooo. oooooooooooo ooooooooooooo oooooooooo. ...
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### Gregorian to Noxu Time System Conversion

The world's changing to a new time system! We need to update our computer programs. Given an input of epoch time (number of seconds since January 1st, 1970 00:00), print out a time in the new Noxu ...
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### Determine which of two ImageMagick .TXT images is more saturated

You have two images (64x64 pixels each): Your program must take the file names of each of them as command line arguments and determine which has more average saturation among their pixels. The ...
299 views

### Compact a Befunge program

Befunge is a 2-dimensional esoteric programming language. The basic idea is that (one-character) commands are placed on a 2-dimensional grid. Control flow walks across the grid, executing commands it ...
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### Implementing bool() without any conditionals

Title says it all. Given some input, turn it into a boolean value (0 or 1), without using conditional statements (e.x. == > < <= >= != ~=), or any function which uses conditional ...
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### Emulate a 7-segment display

Task The task is to display any of the 128 possible states of a 7-segment display. Your program should accept a string of 7 characters ("bits") that are either 0 or 1. First bit of input corresponds ...
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### Convert the Binary Champernowne Constant to Decimal

The Champernowne constant is a transcendental decimal number whose digits are the concatination of all positive integers. C10 = 0.12345678910111213141516...10 The binary version of this is C2 = ...
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### Generate Esolangs

Given a file named hello_world that contains 2-100 bytes of printable ASCII, create a Turing-complete language in which hello_world is a valid program that prints "Hello World!". The output should be ...
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### Cryptographic quine variant

Create a program that prints the MD5 sum of its source in the form: MD5 sum of my source is: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx No cheating - you can't just read the source file and compute its sum. ...
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### Write a program that uses all printable non-alphanumeric ASCII symbols

In particular, use each of these symbols at least once in your source code: ! " # \$ % & ' () * + , - . / : ; < = > ? @ [ \ ] ^ _ ` { | } ~ Symbols inside comments, string literals, ...
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### Determine the original sequence

Write a program that will determine the original sequence given five variations. The original sequence will be contain n unique elements in any order. A variation is made by making a copy of the ...
503 views

### The Strange Unsorting Machine for Nefarious Purposes

Good Evening Golfers! Your challenge is to completely unsort a series of numbers. Input Exactly 100 integers will be fed to your program. Your program may accept the input either as a file, or via ...
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### Ode-cay Olf-gay

Write a program which accepts a sentence into stdin, and writes that sentence to stdout in pig latin. Here are some test cases which your program should handle: Input: Read your script Output: ...
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### Bob's Financial Planning (Maximize)

Bob's Financial Planning Bob lives in Pecunia. It is a small island city completely governed by the Pecunia City Council (PCC). PCC has decided to encourage foreign investments in the city by waiving ...
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### Program my microwave oven

I'm very lazy so I try to always program my microwave with the fewest possible button presses. My microwave has the following buttons: A "minute plus" button which may only be pressed first and ...
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### Turing Machine Simulator

Write a Turing machine simulator. For simplicity we can assume statuses as integer, symbols as char, blank symbol equals whitespace 5-tuple in the form of current state, input symbol, next state, ...
460 views

### Find the Pisano Period of a number

Input: An integer 0 < n < 2^30, taken from stdin. Output: The Pisano period of n (the length of the cycle of the Fibonacci sequence mod n) Input is smaller than 2^30 so that intermediate ...
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### RPN calculator without pointers

Me and some other students were at a bar discussing programming languages, in particular the C programming language. At some point a first year student said he didn't need no damn pointers. Another ...