[AOC2023][Typescript] Added solutions for Day 8.

Author: FlorianDe

Diff for: README.md

@@ -26,6 +26,7 @@
 | [05 - If You Give A Seed A Fertilizer](https://adventofcode.com/2023/day/5)                          | [Day 05 TypeScript](/typescript/src/2023/day05.ts) | 
 | [06 - Wait For It](https://adventofcode.com/2023/day/6)                                              | [Day 06 TypeScript](/typescript/src/2023/day06.ts) | 
 | [07 - Camel Cards](https://adventofcode.com/2023/day/7)                                              | [Day 07 TypeScript](/typescript/src/2023/day07.ts) | 
+| [08 - Haunted Wasteland](https://adventofcode.com/2023/day/8)                                        | [Day 08 TypeScript](/typescript/src/2023/day08.ts) | 
 
 ### AoC 2022 
 | Day                                                                                                  | Kotlin                                                                          | TypeScript                                         | 

Diff for: typescript/src/2023/day08.ts

@@ -0,0 +1,43 @@
+import {AocDay, AocDayDecorator, SolutionParts} from "../aoc";
+import {Maths} from "../aoc/math";
+
+@AocDayDecorator('2023', '8')
+export class Day08 extends AocDay {
+
+	solveImpl(): SolutionParts {
+		type RLInstruction = "R" | "L"
+		type Node = string;
+		type DirectionEntry = Record<RLInstruction, Node>;
+
+		const [rightLeftInstructionsRow, directionsStr] = this.input.split("\n\n");
+
+		const rightLeftInstructions = rightLeftInstructionsRow.trim().split("") as RLInstruction[];
+		const directionMap: Record<Node, DirectionEntry> = Object.fromEntries(directionsStr.split("\n").map(row => {
+			const [start, endsPart] = row.split("=").map(p => p.trim());
+			const [left, right] = endsPart.replaceAll(/[()]/g, "").split(",").map(p => p.trim());
+			return [start, {'L': left, 'R': right}];
+		}));
+
+		const traverseMap = (startNode: Node, isEndNodePredicate: (node: Node) => boolean): number => {
+			let node = startNode;
+			let turns = 0;
+			do{
+				node = directionMap[node][rightLeftInstructions[turns%rightLeftInstructions.length]];
+				turns++;
+			} while (!isEndNodePredicate(node));
+			return turns;
+		};
+
+		const part1 = () => traverseMap("AAA", (n) => n === "ZZZ");
+		const part2 = () =>  Maths.Arithmetics.lcm(
+			Object.keys(directionMap)
+				.filter(node => node.endsWith("A"))
+				.map(startNode => traverseMap(startNode, (n) => n.endsWith("Z")))
+		);
+
+		return {
+			part1: part1(),
+			part2: part2()
+		};
+	}
+}

Diff for: typescript/src/2023/index.ts

@@ -4,4 +4,5 @@ export * from './day03';
 export * from './day04';
 export * from './day05';
 export * from './day06';
-export * from './day07';
+export * from './day07';
+export * from './day08';

Diff for: typescript/src/aoc/math/index.ts

@@ -0,0 +1,2 @@
+export * from "./maths";
+export * from "./point";

Diff for: typescript/src/aoc/math/maths.ts

@@ -0,0 +1,27 @@
+export namespace Maths {
+	export namespace Arithmetics {
+		export function gcd(a: number, b: number): number {
+			let aCopy = a;
+			let bCopy = b;
+			while (bCopy !== 0) {
+				const temp = bCopy;
+				bCopy = aCopy % bCopy;
+				aCopy = temp;
+			}
+			return aCopy;
+		}
+
+		export function lcm(numbers: number[]): number {
+			if (numbers.length < 2) {
+				throw new Error("At least two numbers are required to find the LCM.");
+			}
+			const lcmImpl = (a: number, b: number) => (a * b) / gcd(a, b);
+
+			let tempLcm = numbers[0];
+			for (let i = 1; i < numbers.length; i++) {
+				tempLcm = lcmImpl(tempLcm, numbers[i]);
+			}
+			return tempLcm;
+		}
+	}
+}