AoC 2023 Day 07 revisited

aoc-2023-day-07-revisited.js

import { map, sort, sum } from "../../lib/arrays.js";
import { pipe } from "../../lib/utils.js";

const parse = input =>
  input
    .split("\n")
    .map(row => row.split(" "))
    .map(([hand, bid]) => [[...hand], Number(bid)]);

const RANKING_PT1 = "23456789TJQKA";
const RANKING_PT2 = "J23456789TQKA";

const cardCount = rankOrder => hand =>
  hand.reduce(
    (cnt, value) => (cnt[rankOrder.indexOf(value)]++, cnt),
    [...rankOrder].fill(0)
  );
const cardStrengths = rankOrder => hand =>
  hand.map(value => rankOrder.indexOf(value).toString(16));

const rank1 = hand =>
  cardCount(RANKING_PT1)(hand)
    .sort((a, b) => b - a)
    .concat(cardStrengths(RANKING_PT1)(hand))
    .join("");

const rank2 = hand => {
  const count = cardCount(RANKING_PT2)(hand);
  const jokers = count.shift();
  count.sort((a, b) => b - a);
  count[0] += jokers;
  return count
    .concat(cardStrengths(RANKING_PT2)(hand))
    .join("");
};

const totalWinnings = rankfn =>
  pipe(
    parse,
    map(([hand, bid]) => [rankfn(hand), bid]),
    sort(([a], [b]) => (a < b ? -1 : 1)),
    map(([, bid], i) => bid * (i + 1)),
    sum
  );

export const part1 = totalWinnings(rank1);
export const part2 = totalWinnings(rank2);