• https://adventofcode.com/2021
• https://2021-aoc-templates.util.repl.co/
• https://github.com/Bogdanp/awesome-advent-of-code

The notes below cover non-Clojure implementations of solutions.

The base implementation is an iteration holding on to the current depth with an optional previous depth.

Other related implementations use partitioning and sliding window approaches.

• Kotlin https://www.youtube.com/watch?v=4A2WwniJdNc

Reasonable windowing implementation with count and a predicate rule.

input.windowed(size: 2).count { (a, b) -> a < b }

• Ruby zip

• Python https://www.youtube.com/watch?v=e_PWnVXa_II&list=PLDeBWauprDRjbplIuyhVhXhIt7k4NuOad&index=2

Structural Pattern Matching used in a number of implementations.

• TypeScript

Most implementations just looked at a basic case lookup but looked at a position update rather than the conditional blocks.

Alternatively look at move[direction](increment)(position):

type Point = {
    x: number;
    y: number;
};

const move = {
    forward: (inc: number) => (p: Point) => {
        p.x += inc;
        return p;
    },
    up: (inc: number) => (p: Point) => {
        p.y -= inc;
        return p;
    },
    down: (inc: number) => (p: Point) => {
        p.y += inc;
        return p;
    },
};