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);