AdventOfCode-ts-2023/8/8_2.ts

import { Inspect, LoadInput } from "../common.ts";
import { ParseMap, GetNextNodeInMap, type MapNodeTree } from "./8_common.ts";

const tests = [
    "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)",
];

const input = await LoadInput(8);

const [directions, map] = ParseMap(input);

// Get a list of all node ID's starting with A
let nodeList: Array<keyof MapNodeTree|undefined> = Object.keys(map).filter((nodeID) => nodeID[2] == "A");
let cycleLengths = [...nodeList.keys()].fill(0, 0, nodeList.length);
/** The total amount of steps taken */
let stepsTaken = 0;

do {
    for (let i = 0; i < nodeList.length; i++) {
        const currNodeID: keyof MapNodeTree|undefined = nodeList[i];
        let nextNodeID: keyof MapNodeTree|undefined;
        if (currNodeID) {
            nextNodeID = GetNextNodeInMap(directions, map, currNodeID, stepsTaken);
            
            if (typeof nextNodeID == "string") {
                nodeList[i] = nextNodeID;

                if (nextNodeID[2] == "Z") {
                    if (cycleLengths[i] == 0) {
                        cycleLengths[i] = stepsTaken;
                    }
                    else {
                        nodeList[i] = undefined;
                        cycleLengths[i] = stepsTaken - cycleLengths[i];
                        console.log(`Index ${i} has a cycle length of ${stepsTaken}`);
                    }
                }
            }
            else {
                throw new Error(`Ran into an empty node after ${stepsTaken} steps`);
            }
        }
    }
    stepsTaken++;
} while (nodeList.filter((n) => !!n).length);

// TODO -- Add LCM finder

console.log(`You'll need to now find the Least Common Multiple for the following values`);
console.log(cycleLengths);