day(22): add solution to part 2
Signed-off-by: Matej Focko <mfocko@redhat.com>
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c4afd4b86d
commit
d93cc98f22
2 changed files with 70 additions and 18 deletions
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@ -30,3 +30,9 @@ fun readGraph(day: Int, name: String) = readInput(day, name).fold(mapOf<String,
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* Converts string to md5 hash.
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*/
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fun String.md5(): String = BigInteger(1, MessageDigest.getInstance("MD5").digest(toByteArray())).toString(16)
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fun <A, B, C> product(xs: Sequence<A>, ys: Sequence<B>, zs: Sequence<C>): Sequence<Triple<A, B, C>> =
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xs.flatMap { x -> ys.flatMap { y -> zs.map { z -> Triple(x, y, z) } } }
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fun <A, B, C> product(xs: Iterable<A>, ys: Iterable<B>, zs: Iterable<C>): Sequence<Triple<A, B, C>> =
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product(xs.asSequence(), ys.asSequence(), zs.asSequence())
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@ -1,10 +1,16 @@
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package year2021.day22
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import product
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import readInput
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// region global extensions
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// region Global extensions
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fun IntRange.intersect(other: IntRange): IntRange = maxOf(first, other.first)..minOf(last, other.last)
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// endregion global extensions
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fun IntRange.size(): Long = if (isEmpty()) 0L else last - first + 1L
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fun IntRange.splitBy(other: IntRange): Sequence<IntRange> =
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sequenceOf(first until other.first, other, other.last + 1..last)
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.map { it.intersect(this) }
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.filterNot(IntRange::isEmpty)
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// endregion Global extensions
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// region State
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enum class State {
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@ -25,25 +31,56 @@ data class Point(val x: Int, val y: Int, val z: Int) {
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}
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// endregion Point
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// region Cube
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data class Cube(val xRange: IntRange, val yRange: IntRange, val zRange: IntRange) {
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// region Cuboid
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data class Cuboid(val xRange: IntRange, val yRange: IntRange, val zRange: IntRange) {
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val allPoints: Iterable<Point>
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get() = xRange.flatMap { x -> yRange.flatMap { y -> zRange.map { z -> Point(x, y, z) } } }
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fun intersect(other: Cube): Cube = Cube(
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val size: Long
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get() = xRange.size() * yRange.size() * zRange.size()
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fun intersect(other: Cuboid): Cuboid = Cuboid(
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xRange = xRange.intersect(other.xRange),
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yRange = yRange.intersect(other.yRange),
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zRange = zRange.intersect(other.zRange),
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)
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private fun isEmpty(): Boolean = xRange.isEmpty() || yRange.isEmpty() || zRange.isEmpty()
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operator fun minus(other: Cuboid): Set<Cuboid> {
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val overlap = this.intersect(other)
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return if (overlap.isEmpty()) {
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setOf(this)
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} else if (overlap == this) {
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emptySet()
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} else {
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buildSet {
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for ((xs, ys, zs) in product(
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xRange.splitBy(overlap.xRange),
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yRange.splitBy(overlap.yRange),
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zRange.splitBy(overlap.zRange),
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)) {
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if (
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xs.first !in overlap.xRange
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|| ys.first !in overlap.yRange
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|| zs.first !in overlap.zRange
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) {
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add(Cuboid(xs, ys, zs))
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}
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}
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}
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}
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}
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}
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// endregion Cube
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// endregion Cuboid
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// region Step
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data class Step(val state: State, val cube: Cube) {
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data class Step(val state: State, val cuboid: Cuboid) {
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val allPoints: Iterable<Point>
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get() = cube.allPoints
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get() = cuboid.allPoints
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fun crop(cube: Cube): Step = this.copy(cube = this.cube.intersect(cube))
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fun crop(cuboid: Cuboid): Step = this.copy(cuboid = this.cuboid.intersect(cuboid))
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}
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fun String.toStep(): Step {
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@ -54,12 +91,12 @@ fun String.toStep(): Step {
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.map { it.split("=")[1].split("..").map(String::toInt) }
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.map { it[0]..it[1] }
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return Step(state.toState(), Cube(xRange, yRange, zRange))
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return Step(state.toState(), Cuboid(xRange, yRange, zRange))
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}
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// endregion Step
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fun part1(input: List<Step>): Int = input.fold(mutableSetOf<Point>()) { turnedOn, step ->
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val croppedStep = step.crop(Cube(-50..50, -50..50, -50..50))
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val croppedStep = step.crop(Cuboid(-50..50, -50..50, -50..50))
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when (step.state) {
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State.On -> turnedOn.addAll(croppedStep.allPoints)
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State.Off -> turnedOn.removeAll(croppedStep.allPoints)
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@ -68,14 +105,23 @@ fun part1(input: List<Step>): Int = input.fold(mutableSetOf<Point>()) { turnedOn
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turnedOn
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}.size
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fun part2(input: List<Step>): Long = input.fold(mutableSetOf<Triple<Int, Int, Int>>()) { turnedOn, step ->
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when (step.state) {
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State.On -> turnedOn.addAll(step.allPoints.map { Triple(it.x, it.y, it.z) })
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State.Off -> turnedOn.removeAll(step.allPoints.map { Triple(it.x, it.y, it.z) })
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}
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// region Reactor
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data class Reactor(val cuboids: List<Cuboid> = emptyList()) {
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fun execute(step: Step): Reactor {
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// remove current one from turned on
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val withoutStep = cuboids.flatMapTo(mutableListOf()) { it - step.cuboid }
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if (step.state == State.On) {
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withoutStep.add(step.cuboid)
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}
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turnedOn
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}.size.toLong()
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return copy(cuboids = withoutStep)
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}
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}
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// endregion Reactor
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fun part2(input: List<Step>): Long = input.fold(Reactor()) { reactor, step ->
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reactor.execute(step)
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}.cuboids.sumOf { it.size }
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fun main() {
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val smallerSample = readInput(22, "smaller_sample").map(String::toStep)
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