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day(19): add solution

Signed-off-by: Matej Focko <mfocko@redhat.com>
This commit is contained in:
Matej Focko 2021-12-19 17:37:36 +01:00
parent 3701f6ffdf
commit b5718fdb3b
3 changed files with 268 additions and 0 deletions

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@ -11,6 +11,7 @@ private fun openFile(day: Int, name: String) = File("src/year%4d/day%02d".format
*/
fun readInput(day: Int, name: String) = openFile(day, name).readLines()
fun readInputAsString(day: Int, name: String) = openFile(day, name).readText()
fun readInputAsInts(day: Int, name: String) = readInput(day, name).map { it.toInt() }
fun readInputAsCommaSeparatedInts(day: Int, name: String) = openFile(day, name)
.readText()

131
src/year2021/day19/Day19.kt Normal file
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@ -0,0 +1,131 @@
package year2021.day19
import readInputAsString
import java.time.Instant
import java.util.*
import kotlin.math.absoluteValue
import kotlin.math.sin
import kotlin.math.cos
import kotlin.math.sqrt
data class Vector(val x: Int, val y: Int, val z: Int) {
fun magnitude(): Double = sqrt((x * x + y * y + z * z).toDouble())
fun translate(by: Vector): Vector = this - by
fun rotate(u: Vector, v: Vector, w: Vector): Vector =
Vector(
u.x * x + v.x * y + w.x * z,
u.y * x + v.y * y + w.y * z,
u.z * x + v.z * y + w.z * z,
)
operator fun plus(v: Vector): Vector = Vector(x + v.x, y + v.y, z + v.z)
operator fun minus(v: Vector): Vector = Vector(x - v.x, y - v.y, z - v.z)
operator fun unaryMinus(): Vector = Vector(-x, -y, -z)
operator fun times(c: Int): Vector = Vector(c * x, c * y, c * z)
}
data class Scanner(val beacons: Set<Vector>)
// region parsing
fun String.toVector() =
this.split(",").map(String::toInt).let { (x, y, z) ->
Vector(x, y, z)
}
fun String.toScanner() =
Scanner(this.split("\n").drop(1).map(String::toVector).toSet())
// endregion
// region constants
val TRIGONOMETRY: Set<Pair<Int, Int>> =
listOf(0, 90, 180, 270)
.map { Math.toRadians(it.toDouble()) }
.map { sin(it).toInt() to cos(it).toInt() }
.toSet()
val ROTATIONS: Set<Triple<Vector, Vector, Vector>> =
TRIGONOMETRY
.flatMap { alpha -> TRIGONOMETRY.flatMap { beta -> TRIGONOMETRY.map { gamma -> Triple(alpha, beta, gamma) } } }
.map { (a, b, g) ->
val (sinA, cosA) = a
val (sinB, cosB) = b
val (sinG, cosG) = g
Triple(
Vector(cosA * cosB, sinA * cosB, -sinB),
Vector(cosA * sinB * sinG - sinA * cosG, sinA * sinB * sinG + cosA * cosG, cosB * sinG),
Vector(cosA * sinB * cosG + sinA * sinG, sinA * sinB * cosG - cosA * sinG, cosB * cosG)
)
}
.toSet()
// endregion
fun checkOverlap(beacons: Set<Vector>, scanner: Scanner): Pair<Vector, List<Vector>>? {
ROTATIONS.forEach { (u, v, w) ->
val rotatedBeacons = scanner.beacons.map { it.rotate(u, v, w) }
beacons.forEach { anchor -> // anchor from already located beacons
val translateWithRegardsToAnchor = beacons.map { it.translate(anchor) }.toSet()
rotatedBeacons.forEach { rotatedAnchor ->
val translateWithRegardsToRotatedAnchor = rotatedBeacons.map { it.translate(rotatedAnchor) }.toSet()
val intersect = translateWithRegardsToAnchor.intersect(translateWithRegardsToRotatedAnchor)
if (intersect.size >= 12) {
val scannerPosition = rotatedAnchor - anchor
val translatedBeacons = rotatedBeacons.map { it - rotatedAnchor + anchor }
return scannerPosition to translatedBeacons
}
}
}
}
return null
}
fun locate(scanners: List<Scanner>): Pair<Set<Vector>, Set<Vector>> {
val beacons = mutableSetOf<Vector>()
val scannerPositions = mutableSetOf<Vector>()
// add first scanner that is used as anchor
beacons.addAll(scanners.first().beacons)
val remainingScanners = scanners.drop(1).toMutableList()
while (remainingScanners.isNotEmpty()) {
for (i in remainingScanners.indices.reversed()) {
val (scannerPosition, translatedBeacons) = checkOverlap(beacons, remainingScanners[i]) ?: continue
beacons.addAll(translatedBeacons)
scannerPositions.add(scannerPosition)
remainingScanners.removeAt(i)
println("Done: ${scanners.size - remainingScanners.size}/${scanners.size}")
}
}
return scannerPositions to beacons
}
fun part1(input: Set<Vector>): Int = input.size
fun part2(input: Set<Vector>): Int =
input.maxOf { a ->
input.maxOf { b ->
(a.x - b.x).absoluteValue + (a.y - b.y).absoluteValue + (a.z - b.z).absoluteValue
}
}
fun main() {
val sample =
readInputAsString(19, "sample").split("\n\n").map(String::toScanner)
val input =
readInputAsString(19, "input").split("\n\n").map(String::toScanner)
println(Date.from(Instant.now()))
val (sampleScanners, sampleBeacons) = locate(sample)
check(part1(sampleBeacons) == 79)
check(part2(sampleScanners) == 3621)
val (inputScanners, inputBeacons) = locate(input)
println(part1(inputBeacons))
println(part2(inputScanners))
println(Date.from(Instant.now()))
}

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@ -0,0 +1,136 @@
--- scanner 0 ---
404,-588,-901
528,-643,409
-838,591,734
390,-675,-793
-537,-823,-458
-485,-357,347
-345,-311,381
-661,-816,-575
-876,649,763
-618,-824,-621
553,345,-567
474,580,667
-447,-329,318
-584,868,-557
544,-627,-890
564,392,-477
455,729,728
-892,524,684
-689,845,-530
423,-701,434
7,-33,-71
630,319,-379
443,580,662
-789,900,-551
459,-707,401
--- scanner 1 ---
686,422,578
605,423,415
515,917,-361
-336,658,858
95,138,22
-476,619,847
-340,-569,-846
567,-361,727
-460,603,-452
669,-402,600
729,430,532
-500,-761,534
-322,571,750
-466,-666,-811
-429,-592,574
-355,545,-477
703,-491,-529
-328,-685,520
413,935,-424
-391,539,-444
586,-435,557
-364,-763,-893
807,-499,-711
755,-354,-619
553,889,-390
--- scanner 2 ---
649,640,665
682,-795,504
-784,533,-524
-644,584,-595
-588,-843,648
-30,6,44
-674,560,763
500,723,-460
609,671,-379
-555,-800,653
-675,-892,-343
697,-426,-610
578,704,681
493,664,-388
-671,-858,530
-667,343,800
571,-461,-707
-138,-166,112
-889,563,-600
646,-828,498
640,759,510
-630,509,768
-681,-892,-333
673,-379,-804
-742,-814,-386
577,-820,562
--- scanner 3 ---
-589,542,597
605,-692,669
-500,565,-823
-660,373,557
-458,-679,-417
-488,449,543
-626,468,-788
338,-750,-386
528,-832,-391
562,-778,733
-938,-730,414
543,643,-506
-524,371,-870
407,773,750
-104,29,83
378,-903,-323
-778,-728,485
426,699,580
-438,-605,-362
-469,-447,-387
509,732,623
647,635,-688
-868,-804,481
614,-800,639
595,780,-596
--- scanner 4 ---
727,592,562
-293,-554,779
441,611,-461
-714,465,-776
-743,427,-804
-660,-479,-426
832,-632,460
927,-485,-438
408,393,-506
466,436,-512
110,16,151
-258,-428,682
-393,719,612
-211,-452,876
808,-476,-593
-575,615,604
-485,667,467
-680,325,-822
-627,-443,-432
872,-547,-609
833,512,582
807,604,487
839,-516,451
891,-625,532
-652,-548,-490
30,-46,-14