adventofcode/2022/05/part1.js

import * as R from "remeda";

import fs from "fs-extra";
import path from "path";
import { fileURLToPath } from "url";

export const readFile = (url, file) =>
  fs.readFileSync(path.join(fileURLToPath(new URL(".", url)), file), "utf8");

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

function parseHeaps(text) {
  const lines = text.split("\n").filter(R.identity);
  lines.reverse();

  let [header, ...crates] = lines;

  const stacks = [];

  while (header.trimEnd()) {
    header = header.replace(/^(\s+)\d/, (...args) => {
      crates = crates.map((c) => c.slice(args[1].length));

      const stack = [];

      crates = crates.map((l) =>
        l.replace(/./, (c) => {
          if (c !== " ") stack.push(c);
          return "";
        })
      );

      stacks.push(stack);

      return "";
    });
  }

  return stacks;
}

function parseCommands(text) {
  return text
    .split("\n")
    .filter(R.identity)
    .map((line) => line.match(/\d+/g).map((x) => parseInt(x)));
}

function moveStacks([stacks, commands]) {
  for (let [move, from, to] of commands) {
    console.log({ move, from, to });

    while (move-- > 0) {
      stacks[to - 1].push(stacks[from - 1].pop());
    }
  }

  return stacks;
}

export const spy = (x) => {
  console.log(x);
  return x;
};

export const parseLines = ([heaps, commands]) => [
  parseHeaps(heaps),
  parseCommands(commands),
];

export const solutionPart1 = R.createPipe(
  (text) => text.split("\n\n"),
  parseLines,
  moveStacks,
  R.map((x) => x.pop()),
  (x) => x.join("")
);