advent-of-code-2023/src/day_eight.test.ts

import {DesertMap, lcm} from "./day_eight";

describe('Day Eight', () => {
	const input = `RL

AAA = (BBB, CCC)
BBB = (DDD, EEE)
CCC = (ZZZ, GGG)
DDD = (DDD, DDD)
EEE = (EEE, EEE)
GGG = (GGG, GGG)
ZZZ = (ZZZ, ZZZ)`;

	const repeatedInput = `LLR

AAA = (BBB, BBB)
BBB = (AAA, ZZZ)
ZZZ = (ZZZ, ZZZ)`

	const ghostInput = `LR

11A = (11B, XXX)
11B = (XXX, 11Z)
11Z = (11B, XXX)
22A = (22B, XXX)
22B = (22C, 22C)
22C = (22Z, 22Z)
22Z = (22B, 22B)
XXX = (XXX, XXX)`

	it('should calculate the number of steps needed to reach ZZZ', () => {
		const map = new DesertMap(input);
		expect(map.stepsToZ('AAA')).toEqual(2);
	});

	it('should repeat the pattern', () => {
		const map = new DesertMap(repeatedInput);
		expect(map.stepsToZ('AAA')).toEqual(6);
	});

	it('should count how many steps it takes to get from every node beginning with A, to every node ending in Z simultaneously', () => {
		const map = new DesertMap(ghostInput);
		expect(map.ghostStepsToZ()).toEqual(6);
	});

	describe('lcm', () => {
		it('should get the correct lowest common multiple', () => {
			expect(lcm(12, 30)).toEqual(60);
		});
	});
});