17 questions linked to/from Tips for golfing in x86/x64 machine code
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### Greatest Common Divisor

Your task is to compute the greatest common divisor (GCD) of two given integers in as few bytes of code as possible. You may write a program or function, taking input and returning output via any of ...
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### Swap the parity

Task Given a positive integer n, output n+1 if n is odd, and output ...
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### Is it a Cyclops number? “Nobody” knows!

Task: Given an integer input, figure out whether or not it is a Cyclops Number. What is a Cyclops number, you may ask? Well, it's a number whose binary representation only has one ...
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### The Luhn algorithm for verifying credit card numbers, etc

Challenge Write the shortest program or function to calculate the Luhn Algorithm for verifying (credit card) numbers. Luhn algorithm explained From RosettaCode, this algorithm for the purposes of ...
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### User Appreciation Challenge #1: Dennis ♦

I got the spontaneous idea of making a series of challenges of users that have helped and continue to help the PPCG community be an enjoyable place for everyone, or maybe just specifically for me. :P ...
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### How many steps does it take from n to 1 by subtracting the greatest divisor?

Inspired by this question over at Mathematics. The Problem Let n be a natural number ≥ 2. Take the biggest divisor of ...
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### Binary Fibonacci

Challenge You need to generate a program or function that takes in a positive integer N, calculates the first N terms of the Fibonacci sequence in binary, concatenates it into a single binary number, ...
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### ASCII art uncompression from a base-n number

This is inspired by an 05AB1E answer by Magic Octupus Urn. Given two arguments, a positive integer and a string/list of characters: Translate the number to base-n, where n is the length of the ...
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### Exchange capitalization

Given two strings of letters, transfer the capitalization pattern of each string onto the other one. Fewest bytes wins. ...
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### Can the number be split into powers of 2?

Yesterday while playing with my kid I noticed the number in his toy train: So we have $$4281$$ that can be split into $$4-2-8-1$$ or $$2^2-2^1-2^3-2^0$$ So simple challenge: given a non-negative ...
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### The repetitive byte counter

Your task is to write a non-empty program / function of byte count L, which, when repeated M times, checks whether a given positive integer N is equal to L × M. You should, in theory, support an ...
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### Stewie's sequence: + * - / + * - /

Let's use the four basic operations, addition +, multiplication *, subtraction - and ...
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### The Chroma Key to Success

The RGB color value #00FF00 is a rather important one: it is used to make movies, TV shows, weather announcements, and more. It is the famous "TV green" or "green ...