expeditaet/solutions/typescript/2021/14/src/p1.ts

Advent of Code Solutions

/* eslint-disable @typescript-eslint/no-non-null-assertion */
import { task } from '@alexaegis/advent-of-code-lib';
import packageJson from '../package.json';
import { parse } from './parse.function.js';

const score = (polymer: string[]): number => {
	const elementCounts = polymer.reduce((acc, n) => {
		acc.set(n, (acc.get(n) ?? 0) + 1);
		return acc;
	}, new Map<string, number>());
	const sortedCounts = [...elementCounts.entries()].sort((a, b) => a[1] - b[1]);
	return sortedCounts.at(-1)![1] - sortedCounts[0]![1];
};

/**
 * Initial naive solution
 */
export const p1 = (input: string): number => {
	const { polymer, rules } = parse(input);
	let p = [...polymer];
	for (let generation = 0; generation < 10; generation++) {
		const next: string[] = [];
		for (let i = 0; i < p.length - 1; i = i + 1) {
			next.push(p[i]!);
			const result = rules.get(`${p[i]}${p[i + 1]}`);
			if (result) {
				next.push(result);
			} else {
				next.push(p[i + 1]!);
			}
		}
		next.push(p.at(-1)!);
		p = next;
	}
	return score(p);
};

await task(p1, packageJson.aoc); // 2703 ~1.82ms