advent2022/d15/main.js

const fs = require('fs');
const readline = require('readline');

function taxiCab(a, b) {
    return Math.abs(b[0] - a[0]) + Math.abs(a[1] - b[1]);
}

function Sensor(arr) {
    this.pos = [arr[0], arr[1]];
    this.closestBeacon = [ arr[2], arr[3] ];
    this.dist = taxiCab(this.pos, this.closestBeacon);
}

Sensor.prototype.canBeacon = function(pos) {
    return taxiCab(this.pos, pos) > this.dist || (
        pos[0] === this.closestBeacon[0] && pos[1] === this.closestBeacon[1]);
}

Sensor.prototype.canBeDetress = function(pos) {
    return taxiCab(this.pos, pos) > this.dist;
}

function checkRow(rowId, minX, maxX, sensors) {
    let result = 0;
    for (let i =minX; i < maxX; ++i)
        if (!sensors.every(s => s.canBeacon([i, rowId])))
            result++;
    return result;
}

function checkPos(sensors, maxSize, i, j) {
    if (i < maxSize && j < maxSize && i >= 0 && j >=0 && sensors.every(s => s.canBeDetress([i, j])))
        return [ i, j ];
    return null;
}

function findPos(maxSize, sensors) {
    for (let sensor of sensors) {
        for (let i =0; i <= sensor.dist +1; ++i) {
            let j = sensor.dist +1 - i;
            let result =
                checkPos(sensors, maxSize, sensor.pos[0] + i, sensor.pos[1] + j) ||
                checkPos(sensors, maxSize, sensor.pos[0] + i, sensor.pos[1] - j) ||
                checkPos(sensors, maxSize, sensor.pos[0] - i, sensor.pos[1] - j) ||
                checkPos(sensors, maxSize, sensor.pos[0] - i, sensor.pos[1] + j);
            if (result) {
                console.log(result);
                return 4000000 * result[0] + result[1];
            }
        }
    }
}

async function main() {
    let sensors = [];
    let minX = Infinity;
    let maxX = -Infinity;
    let maxY = -Infinity;
    let maxDist = -Infinity;
    for await (let line of readline.createInterface({ input: process.stdin })) {
        let sensor = new Sensor(line.match(/(-?\d+)/g).map(i => parseInt(i)));
        minX = Math.min(minX, sensor.pos[0]);
        maxX = Math.max(maxX, sensor.pos[0]);
        maxY = Math.max(maxY, sensor.pos[1]);
        maxDist = Math.max(maxDist, sensor.dist);
        sensors.push(sensor);
    }
    // part1
    console.log(checkRow(10, minX -maxDist, maxX + maxDist, sensors));
    console.log(findPos(20, sensors));

    // part2
    console.log(checkRow(2000000, minX -maxDist, maxX + maxDist, sensors));
    console.log(findPos(4000000, sensors));
};

(main());