Advent of Code 2022 14

aoc22-14.kt

import se.saidaspen.aoc.util.*
import kotlin.math.sign


fun main() = Dayxx.run()

object Dayxx : Day(2022, 14) {

    override fun part1() : Any {
//        input = "498,4 -> 498,6 -> 496,6\n" +
//                "503,4 -> 502,4 -> 502,9 -> 494,9"
//        println(input)
        var map = mutableMapOf<P<Int, Int>, Char>()
        var source = P(500,0)
        var lines  = input.lines().flatMap {
            var splits = it.split(" -> ")
            splits.windowed(2)
                .map { l -> positives(l.joinToString(" ")) }
                .map { i -> P(Point(i[0], i[1]), Point(i[2], i[3])) }.toList()
        }
        var linesPoints = lines.flatMap { it.first.lineTo(it.second) }
        linesPoints.forEach { map[it] = '#' }

        var maxY = linesPoints.map { it.second }.max()
        var currSand = source
        var cnt = 0
        while(true) {
            if (currSand.second >= maxY) {
                break
            }
            if (!map.containsKey(currSand + Point(0, 1))) {
                currSand += Point(0, 1)
            } else if (!map.containsKey(currSand + Point(-1, 1))) {
                currSand += Point(-1, 1)
            } else if (!map.containsKey(currSand + Point(1, 1))) {
                currSand += Point(1, 1)
            } else {
                cnt += 1
                map[currSand] = 'o'
                currSand = source
            }
        }
        return cnt
    }

    override fun part2(): Any {
//        input = "498,4 -> 498,6 -> 496,6\n" +
//                "503,4 -> 502,4 -> 502,9 -> 494,9"
        println(input)
        var map = mutableMapOf<P<Int, Int>, Char>()
        var source = P(500,0)
        var lines  = input.lines().flatMap {
            var splits = it.split(" -> ")
            splits.windowed(2)
                .map { l -> positives(l.joinToString(" ")) }
                .map { i -> P(Point(i[0], i[1]), Point(i[2], i[3])) }.toList()
        }
        var linesPoints = lines.flatMap { it.first.lineTo(it.second) }
        linesPoints.forEach { map[it] = '#' }

        var maxY = linesPoints.map { it.second }.max()
        var floor = maxY + 2
        var currSand = source
        var moved = 0
        var cnt = 0
        while(true) {
            if (currSand == source
                && map.containsKey(currSand + Point(0, 1))
                && map.containsKey(currSand + Point(1, 1))
                && map.containsKey(currSand + Point(-1, 1))
            ) {
                break
            }
            if (!map.containsKey(currSand + Point(0, 1)) && currSand.second + 1 < floor) {
                currSand += Point(0, 1)
                moved += 1
            } else if (!map.containsKey(currSand + Point(-1, 1)) && currSand.second + 1 < floor) {
                currSand += Point(-1, 1)
                moved += 1
            } else if (!map.containsKey(currSand + Point(1, 1)) && currSand.second + 1 < floor) {
                currSand += Point(1, 1)
                moved += 1
            } else {

                cnt += 1
                map[currSand] = 'o'
                currSand = source
            }
        }
        return cnt +1
    }

}

private fun Point.lineTo(other: Point): MutableList<Point> {
    var step = (other - this).sign()
    var line = mutableListOf<Point>()
    var curr = this
    while (curr != other) {
        line.add(curr)
        curr += step
    }
    line.add(curr)
    return line
}

private fun Point.sign(): Point {
    return Point(this.x.sign, this.y.sign)
}