Module day23

Unstable Diffusion

We represent elves as bits in a integer then use bitwise operations to efficiently figure out the movement for multiple elves at once.

Structs

Input

U256

Duct tape two u128s together.

Enums

Direction 🔒

Constants

HEIGHT 🔒

The initial grid is 70 x 70. Elves stop moving when no other elf is adjacent so the grid will expand at most 70 in any direction, giving 70 + 70 + 70 = 210 total.

Functions

parse

Converts the ASCII grid into a bit per elf.

part1

part2

step 🔒