expeditaet/solutions/typescript/2021/11/src/p1.ts

Advent of Code Solutions

import { task } from '@alexaegis/advent-of-code-lib';
import { Direction, GridGraph } from '@alexaegis/advent-of-code-lib/model';
import packageJson from '../package.json';

const flash = (graph: GridGraph<number>, flashed = new Set<string>()): Set<string> => {
	const flashes = [...graph.nodes]
		.filter(([key, node]) => node.value > 9 && !flashed.has(key))
		.tap(([key, node]) => {
			flashed.add(key);
			for (const neightbour of node.neighbours.values())
				neightbour.to.updateValue((v) => v + 1);
		}).length;
	if (flashes) {
		flash(graph, flashed);
	}
	return flashed;
};

export const next = (graph: GridGraph<number>): number => {
	for (const node of graph) {
		node.updateValue((v) => v + 1); // Increment everything by 1
	}

	const flashed = flash(graph); // Flash 9s
	for (const key of flashed) graph.getNode(key)?.setValue(0); // All flashed set to 0
	return flashed.size;
};

export const p1 = (input: string, totalSteps = 100): number => {
	const graph = input.toGridGraph({
		valueConverter: (s) => s.tryInt(),
		connectionDirections: Direction.allDirections,
	});
	return totalSteps
		.iterate()
		.map(() => next(graph))
		.sum();
};

await task(p1, packageJson.aoc); // 1669 ~4.74ms