adventofcode/2022/02/part1.js

import * as R from "remeda";
import fs from "fs-extra";
import path from "path";

export const sampleInput = `A Y
B X
C Z`;

export const puzzleInput = fs.readFileSync(
  path.join(path.dirname(import.meta.url), "input").replace("file:", ""),
  "utf8"
);

const playMap = {
  X: "A", // rock
  Y: "B", // paper
  Z: "C", // scissors
};

export const parseInput = R.createPipe(
  (text) => text.split("\n"),
  R.filter(R.identity), // remove last line
  R.map((entry) => entry.split(" "))
);

export const movePositions = ["A", "B", "C"];

const playScore = {
  A: 1,
  B: 2,
  C: 3,
};

const draw = 3;
const lost = 0;
const win = 6;

const outcome = (opponent, me) => {
  if (opponent === me) return draw;
  if (opponent === "A") {
    return me === "C" ? lost : win;
  }
  if (opponent === "B") {
    return me === "A" ? lost : win;
  }
  return me === "B" ? lost : win;
};

export const mapScores = ([opponent, me]) => [
  outcome(opponent, me),
  playScore[me],
];

export const solutionPart1 = R.createPipe(
  parseInput,
  R.map(([a, b]) => [a, playMap[b]]),
  R.map(mapScores),
  R.map(R.sumBy(R.identity)),
  R.sumBy(R.identity)
);