code-golfarray-manipulation Push Buttons on a Pedestal Fan I don't know about you, but I grew up with fans like this keeping me cool during summer: Source See those four buttons? Those are different speed settings for the fan, ranging from speed 0 (off) to speed 3 (the highest speed). The f...

Halting problem for simplified Brainfuck decision-problem Given a simplified Brainfuck program, you must determine whether it halts. Your program must always halt in finite time. Simplified Brainfuck is Brainfuck with a single simplification: loops ([]) cannot be nested. Sandbox stuff Is th...

Convoluted Truth Time to get creative! The goal is to create a function that accepts one boolean (or equivalent) and returns its truth value. Restrictions No sequence of four characters is allowed to occur more than twice. For this restriction, whitespace does not count as characters, nor do...

Cheat activated Background The game Grand Theft Auto: San Andreas went down to history also thanks to its wide selection of cheats. They're almost 90 and anyone who has ever touched this game, no doubt he tried them all! One cheat is activated (on PC) typing in-game a secret keyword, and then b...

Uniform necklace sampling code-golf restricted-memory The challenge is, given a number \$N\$, to produce a random binary necklace of length \$N\$. All possible necklaces must have the same probability of being chosen. [TODO: more about necklaces] Scoring Solutions are compared first by asympt...

Note, challenge copied from question asked at math.stackexchange. Recently, I attained quite some skill at blowing bubbles. At first I would blow bubbles like this: But then things started getting strange: After a while, I was blowing some pretty weird bubbles: After blowing hundreds, ma...

Golf Me a Text Editor Errm... You see, I seem to have forgotten what program to use to open, read, and write text files. Something like Noteleaf or VSBro or... Hm... You see my conundrum. But never fear! I know some people who can write one. But... Uh... I'm kind of limited on space, so shorter ...

Draw a Hilbert Curve with Slashes Given a positive integer N, draw the Nth iteration of the Hilbert Curve, using only slashes and backslashes (and spaces). The curve will be rotated at a 45 degree angle from its usual depiction. Here's an example for the first 4 iterations: N = 1 \ \/ N =...

Judge a book by its cover code-golf Given an ascii representation of a book cover in the format described below, determine the "popularity index" of the book (the definition of which has been completely made up for this challenge) Popularity Index Let the popularity index of a book be the num...

Solve some diplomatic issues You are given a set of moves in a theoretical Diplomacy game. We're not going to handle validation of moves being legal or not, simply attempt to resolve a turn. Here are the simplified rules to Diplomacy (full rules here): There are two types of units: Armies an...

You are the captain of a world-famous wrestling team. An Olympic-grade match is coming up, and you are determined not to let your team down. You also happen to be a competent programmer, so you are going to write a program to help your team win! You have access to the strength ratings for each o...

Given a 24 hour time, i.e. 20:48, output the nearest time where each physically adjacent pair of digits is also numerically adjacent, i.e. 21:01. That is, each number in the output must differ from the numbers next to it by 1, and the output must be the closest time, forwards or backwards, for w...