adventofcode/2022/16/part1.js

import * as R from "remeda";
import u from "updeep";

import Graph from "graphology";
import { bidirectional } from "graphology-shortest-path";

import { combinations, permutations } from "combinatorial-generators";

import { readFile } from "../05/part1.js";

const parseLine = (line) => {
  const { groups } = line.match(
    /Valve (?<valve>..).*flow rate=(?<flow>\d+).*valves? (?<exits>.*)/
  );
  return [
    groups.valve,
    {
      exits: groups.exits.split(",").map((x) => x.trim()),
      flow: parseInt(groups.flow),
    },
  ];
};
const readInput = (...args) =>
  R.pipe(
    readFile(...args),
    (lines) => lines.split("\n"),
    R.compact, // remove last line
    R.map(parseLine),
    Object.fromEntries
  );

export const puzzleInput = readInput(import.meta.url, "input");
export const sample = readInput(import.meta.url, "sample");

function finalSteam(
  tunnels,
  graph,
  minutesLeft,
  possibilities,
  location = "AA",
  activeSteam = 0
) {
  //console.log(minutesLeft, totalSteam, itinary);

  if (minutesLeft <= 0) return 0;

  if (possibilities.length === 0) return minutesLeft * activeSteam;

  let scores = [];

  for (const next of possibilities) {
    const path = bidirectional(graph, location, next);

    //console.log(path);

    let time = path.length;
    if (time >= minutesLeft) {
      scores.push(minutesLeft * activeSteam);
    } else {
      //console.log({totalSteam, time, activeSteam});
      let ts = time * activeSteam;
      let as = activeSteam + tunnels[next].flow;

      scores.push(
        ts +
          finalSteam(
            tunnels,
            graph,
            minutesLeft - time,
            possibilities.filter((x) => x !== next),
            next,
            as
          )
      );
    }
  }

  return Math.max(...scores);
}

export const buildGraph = (tunnels) => {
  const graph = new Graph();
  Object.keys(tunnels).forEach((x) => graph.addNode(x));

  Object.entries(tunnels).forEach(([location, { exits }]) => {
    exits.forEach((exit) => graph.addEdge(location, exit));
  });

  return graph;
};

export default (tunnels) => {
  const possibilities = Object.keys(tunnels).filter((k) => tunnels[k].flow);

  const graph = buildGraph(tunnels);

  return finalSteam(tunnels, graph, 30, possibilities, "AA", 0, 0);
};