aoc24-07.mts

import { Advent, f, fm, chr, ord } from "advent";
import { Set, Map } from "immutable";

const { compute, computeCheck } = await Advent({ day: 7 });

compute(1, async (input) => {
	const data = input.parse(f.nl(f.match`${fm.int().as("ans")}: ${fm.list(fm.int(), " ").as("deps")}`));
	let res = 0;

	for (const { ans, deps } of data) {
		if (ok(ans, deps)) {
			res += ans;
		}
	}

	return res;
});

function ok(ans: number, deps: number[]): boolean {
	if (deps.length === 1) {
		return ans === deps[0];
	}

	return (
		ok(ans, [deps[0] + deps[1], ...deps.slice(2)])
		|| ok(ans, [deps[0] * deps[1], ...deps.slice(2)])
		|| ok(ans, [concat(deps[0], deps[1]), ...deps.slice(2)])
	);
}

function concat(a: number, b: number) {
	const len = b.toString().length;
	return a * Math.pow(10, len) + b;
}