adventofcode/2022/15/part2.js

import * as R from "remeda";
import V from "@yanick/vyktor";

import { spy, mergeRanges } from "./part1.js";

const unbeaconAtLine = (max, targetLine, already) => (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,
      ...already.filter((v) => v.y === targetLine).map((v) => [v.x, v.x]),
    ],
    (ranges) =>
      ranges.sort((a, b) => {
        return a[0] - b[0] || a[1] - b[1];
      }),
    // spy,
    R.map((range) => [Math.max(0, range[0]), Math.min(max, range[1])]),
    mergeRanges
    // spy,
    // R.sumBy( range => range[1] - range[0] + 1 - entriesInRange(targetLine,entries)(range) )
  );

export const findBeacon = (max) => (entries) => {
  const already = entries.flat();

  for (let y = 0; y <= max; y++) {
    const ranges = unbeaconAtLine(max, y, already)(entries);
    if (ranges.length > 1) {
      return y + 4000000 * (ranges[0][1] + 1);
    }

    //        return 'bob';

    //       return x * 4000000 + y;
  }
};

export default findBeacon(4000000);