Continuous Everywhere, Differentiable Nowhere
Objective
Build any function \$f : \mathbb{R} → \mathbb{R}\$ that is continuous everywhere, but differentiable nowhere.
Format
Using floating-point number is permitted. Though it will be preferred to use a datatype that is able to represent arbitrary ...
Background
In the sport of Table Tennis (aka Ping-Pong or Whiff Whaff), two opponents play a sequence of rounds, where each round consists of players hitting a ball back and forth until one player (may or may not be the server) gains a point.
Table Tennis has some official rules that make for a g...
When does hh:mm = mm.ss? code-golf time restricted-time
Let's begin with a thought experiment. You have a clock and a timer, in which you start the timer when the clock shows exactly hh:mm.00.
Clock: The clock employs 24-hour time. So the range of hh is 0<=h<23. (Because 23 inputs are unsolvable...
Objective
Given a matrix of connected box drawing characters, count its genus, the number of plane sections it encloses.
Valid input
The box drawing characters are ─│┌┐└┘├┤┬┴┼╴╵╶╷ (U+2500 U+2502 U+250C U+2510 U+2514 U+2518 U+251C U+2524 U+252C U+2534 U+253C U+2574 U+2575 U+2576 U+2577). The matri...
My phone number (which I will not be sharing here) has a neat property where there is a two digit number, which when iteratively removed from my phone number will eventually remove all the digits. For example if my phone number were
abaababbab
Then by repeatedly removing ab we would eventually ...
