expeditaet/solutions/typescript/2023/01/src/p2.ts

Advent of Code Solutions

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

const numbers = {
	one: '1',
	'1': '1',
	two: '2',
	'2': '2',
	three: '3',
	'3': '3',
	four: '4',
	'4': '4',
	five: '5',
	'5': '5',
	six: '6',
	'6': '6',
	seven: '7',
	'7': '7',
	eight: '8',
	'8': '8',
	nine: '9',
	'9': '9',
} as const;

const numbersAsKeys = Object.keys(numbers) as (keyof typeof numbers)[];

export const p2 = (input: string): number => {
	return input
		.lines()
		.map((line) => {
			let firstDigit: string | undefined;
			let lastDigit: string | undefined;
			for (let i = 0; i < line.length; i++) {
				if (firstDigit === undefined) {
					const maybeFirstDigit = line.slice(i, i + 5);
					const firstTextNumber = numbersAsKeys.find((key) =>
						maybeFirstDigit.startsWith(key),
					);
					if (firstTextNumber) {
						firstDigit = numbers[firstTextNumber];
					}
				}

				if (lastDigit === undefined) {
					const maybeDigit = line.slice(
						Math.max(line.length - i - 5, 0),
						line.length - i,
					);

					const textNumber = numbersAsKeys.find((key) => maybeDigit.endsWith(key));
					if (textNumber) {
						lastDigit = numbers[textNumber];
					}
				}

				if (firstDigit !== undefined && lastDigit !== undefined) {
					break;
				}
			}
			return ((firstDigit ?? '') + (lastDigit ?? '')).toInt();
		})
		.sum();
};

await task(p2, packageJson.aoc); // 53348 ~1.4ms