index.ts

@@ -1,3 +1,3 @@
-import {runDayEight} from "./src/day_eight";
+import {runDaySeven} from "./src/day_seven";
 
-runDayEight();
+runDaySeven();

src/day_eight.test.ts

@@ -1,29 +0,0 @@
-import {DesertMap} 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)`
-
-	it('should calculate the number of steps needed to reach ZZZ', () => {
-		const map = new DesertMap(input);
-		expect(map.stepsTo('ZZZ')).toEqual(2);
-	});
-
-	it('should repeat the pattern', () => {
-		const map = new DesertMap(repeatedInput);
-		expect(map.stepsTo('ZZZ')).toEqual(6);
-	})
-});

src/day_eight.ts

@@ -1,66 +0,0 @@
-import {anyCharOf, newline, uniLetter, whitespace} from "parjs";
-import {between, exactly, manySepBy, manyTill, stringify, then} from "parjs/combinators";
-import fs from "fs";
-
-const patternParser = anyCharOf("LR").pipe(manyTill(newline().pipe(exactly(2))));
-
-const nodeNameParser = uniLetter().pipe(exactly(3), stringify());
-const childParser = nodeNameParser.pipe(manySepBy(", "), exactly(2), between("(", ")"));
-const nodeParser = nodeNameParser.pipe(then(childParser.pipe(between(" = ", whitespace()))))
-
-const parser = patternParser.pipe(then(nodeParser.pipe(manySepBy(whitespace()))));
-
-type Maybe<T> = T | undefined;
-
-type Instruction = "L" | "R";
-type NodeName = string;
-type NodeChildren = [Maybe<NodeName>, Maybe<NodeName>];
-
-export class DesertMap {
-	private readonly pattern: Instruction[];
-
-	private map: Record<NodeName, NodeChildren> = {};
-
-	constructor(input: string) {
-		const [pattern, nodes] = parser.parse(input).value;
-
-		this.pattern = pattern as Instruction[];
-
-		for (const [name, [[leftNode, rightNode]]] of nodes) {
-			if (!this.map[name]) {
-				this.map[name] = [undefined, undefined];
-			}
-			const children = [leftNode !== name ? leftNode : undefined, rightNode !== name ? rightNode : undefined];
-			this.map[name] = children as NodeChildren;
-		}
-	}
-
-	public stepsTo(node: string): number {
-		let step = 0;
-		let curr = "AAA";
-
-		while (curr !== node) {
-			const instruction = this.pattern[step % this.pattern.length];
-
-			const [left, right] = this.map[curr];
-
-			if (instruction === "L" && left) {
-				curr = left;
-			} else if (instruction === "R" && right) {
-				curr = right;
-			}
-
-			if (!curr) return 0;
-
-			step++;
-		}
-		return step;
-	}
-}
-
-export const runDayEight = () => {
-	const input = fs.readFileSync('./inputs/day_eight_input.txt', 'utf-8').trimEnd();
-
-	const map = new DesertMap(input);
-	console.log(map.stepsTo('ZZZ'));
-}