adventofcode/2022/15/part1.js

import * as R from "remeda";

import { passthru } from "../08/part1.js";
import { readFile } from "../05/part1.js";

import V from "@yanick/vyktor";
import { createLogger } from "vite";

const readInput = (...args) =>
  R.pipe(
    readFile(...args),
    (lines) => lines.split("\n"),
    R.compact, // remove last line
    R.map((line) =>
      line
        .match(/x=-?.*?y=-?\d+/g)
        .map((str) => str.match(/-?\d+/g).map((x) => parseInt(x)))
        .map((coords) => V(coords))
    )
  );

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

/** @returns [number,number][] */
export const mergeRanges = (ranges) => {
  return ranges.reduce((accum, range) => {
    if (accum.length === 0) return [range];
    if (R.last(accum)[1] < range[0]) {
      accum.push(range);
    } else {
      R.last(accum)[1] = Math.max(R.last(accum)[1], range[1]);
    }
    return accum;
  }, []);
};

export const spy = passthru((x) => console.log(x));

const entriesInRange = (targetLine, entries) => {
  entries = R.uniqBy(
    entries
      .map(([_, beacon]) => beacon)
      .filter((beacon) => beacon?.y === targetLine),
    (x) => x.toString()
  );

  return (range) => {
    return entries.filter((entry) => entry.x >= range[0] && entry.x <= range[1])
      .length;
  };
};

export const unbeaconAtLine = (targetLine) => (entries) =>
  R.pipe(
    entries,
    R.map(([x, y]) => [x, x.manhattanDistance(y)]),
    R.filter((e) => e[0].y - e[1] <= targetLine && e[0].y + e[1] >= targetLine),
    R.map((e) => {
      const l = e[1] - Math.abs(targetLine - e[0].y);

      return [e[0].x - l, e[0].x + l];
    }),
    spy,
    (ranges) =>
      ranges.sort((a, b) => {
        return a[0] - b[0] || a[1] - b[1];
      }),
    spy,
    mergeRanges,
    spy,
    R.sumBy(
      (range) =>
        range[1] - range[0] + 1 - entriesInRange(targetLine, entries)(range)
    )
  );

export default unbeaconAtLine(2000000);