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Day24 part2

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Hubert Van De Walle 2020-12-24 15:41:30 +01:00
parent 23cb05ad27
commit 5d73f12e43
1 changed files with 45 additions and 17 deletions
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62
days/src/main/kotlin/Day24.kt
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@ -4,6 +4,8 @@ import be.vandewalleh.aoc.utils.input.Day
import be.vandewalleh.aoc.utils.input.Input
import be.vandewalleh.aoc.utils.input.Lines
import be.vandewalleh.aoc.utils.input.createDay
import org.eclipse.collections.api.bag.Bag
import org.eclipse.collections.api.bag.MutableBag
import org.eclipse.collections.api.factory.Bags
@Day(24)
@ -20,29 +22,55 @@ class Day24(@Lines val input: Input<List<String>>) {
val coordinates = coordinates
}
private data class Tile(val directions: List<Direction>)
private fun parseTile(line: String) = "e|se|sw|w|nw|ne".toRegex()
.findAll(line)
.flatMap { it.groupValues }
.map { Direction.valueOf(it.toUpperCase()) }
.toList()
private fun parseTile(line: String): Tile {
val re = "e|se|sw|w|nw|ne".toRegex()
val directions = re.findAll(line).flatMap { it.groupValues }.map { Direction.valueOf(it.toUpperCase()) }
return Tile(directions.toList())
private val tiles = input.value.map { parseTile(it) }.map {
it.map { it.coordinates }
.reduce { acc, ints -> intArrayOf(acc[0] + ints[0], acc[1] + ints[1], acc[2] + ints[2]) }
.toList()
}
fun part1() {
val tiles = input.value.map { parseTile(it) }
val bag = Bags.mutable.empty<List<Int>>()
for (tile in tiles) {
val encountered = tile.directions
.map { it.coordinates }
.reduce { acc, ints -> intArrayOf(acc[0] + ints[0], acc[1] + ints[1], acc[2] + ints[2]) }
.toList()
bag.add(encountered)
fun part1() = Bags.immutable.ofAll(tiles).selectBlacks().size()
private fun Bag<List<Int>>.selectBlacks() = selectByOccurrences { it % 2 == 1 }
private fun List<Int>.adjacents(): List<List<Int>> {
val (x, y, z) = this
return listOf(
listOf(x + 1, y - 1, z),
listOf(x, y - 1, z + 1),
listOf(x - 1, y, z + 1),
listOf(x - 1, y + 1, z),
listOf(x, y + 1, z - 1),
listOf(x + 1, y, z - 1),
)
}
// black -> odd
// white -> even || not in bag -> !in black
private fun day(bag: MutableBag<List<Int>>) {
val blacks = bag.selectBlacks().toSet()
val all = (bag + bag.flatMap { it.adjacents() }).toSet()
for (tile in all) {
val adjacents = tile.adjacents()
val adjacentBlacks = adjacents.count { it in blacks }
val isBlack = tile in blacks
if (isBlack && (adjacentBlacks == 0 || adjacentBlacks > 2)) bag.setOccurrences(tile, 2)
else if (!isBlack && adjacentBlacks == 2) bag.setOccurrences(tile, 1)
}
println(bag.selectByOccurrences { it % 2 == 1 }.size)
}
fun part2() {
fun part2(): Int {
val bag = Bags.mutable.ofAll(tiles)
repeat(100) { day(bag) }
return bag.selectBlacks().size()
}
}