advent-of-code-2023/src/day_four.ts

import fs from "fs";
import {whitespace, int, string} from "parjs";
import {between, manySepBy, then} from "parjs/combinators";

const cardIdParser = int()
	.pipe(between(whitespace()))
	.pipe(between(string('Card'), string(': ')));

const numbersParser = int()
	.pipe(between(whitespace()))
	.pipe(manySepBy(whitespace()));

const winningNumberParser = numbersParser
	.pipe(between(cardIdParser, string('|')))
	.pipe(then(numbersParser));

export class Scratchcard {
	private readonly numbers: number[];
	private readonly winningNumbers: number[];
	private children: Scratchcard[] = [];

	constructor(input: string) {
		const [
			winningNumbers,
			numbers
		] = winningNumberParser.parse(input).value;

		this.winningNumbers = winningNumbers;
		this.numbers = numbers;
	}

	private parseNumberList(input: string): number[] {
		return [...input.matchAll(/\d+/g)].map(match => parseInt(match[0], 10));
	}

	public get matches() {
		return this.numbers.filter(number => this.winningNumbers.includes(number));
	}

	get score() {
		const matches = this.matches;
		if (!matches.length) return 0;

		return Math.pow(2, matches.length - 1);
	}

	get isWinner() {
		return Boolean(this.matches.length);
	}

	public setChildren(children: Scratchcard[]) {
		this.children = children;
	}

	get size(): number {
		return 1 + this.children.reduce((totalSize, child) => totalSize + child.size, 0);
	}
}

export class ScratchcardSet {
	private readonly scratchcards: Scratchcard[];

	constructor(inputs: string[]) {
		this.scratchcards = inputs.map(input => new Scratchcard(input));

		this.scratchcards.forEach((scratchcard, index) => {
			if (scratchcard.isWinner) {
				const children = this.scratchcards.slice(index + 1, index + 1 + scratchcard.matches.length);
				scratchcard.setChildren(children);
			}
		});
	}

	get totalScore() {
		return this.scratchcards.reduce((total, scratchcard) => total + scratchcard.score, 0);
	}

	get length() {
		return this.scratchcards.reduce((totalSize, scratchcard) => totalSize + scratchcard.size, 0);
	}
}

export const runDayFour = () => {
	const input = fs.readFileSync('./inputs/day_four_input.txt', 'utf8').split('\n').filter(Boolean);
	const scratchCards =  new ScratchcardSet(input);

	console.log(scratchCards.totalScore);
	console.log(scratchCards.length);
}