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Optimize part2

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Hubert Van De Walle 2020-12-14 11:19:17 +01:00
parent 1850a2145c
commit e268a50409
1 changed files with 40 additions and 35 deletions
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75
days/src/main/kotlin/Day14.kt
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@ -6,7 +6,7 @@ import be.vandewalleh.aoc.utils.input.Lines
import be.vandewalleh.aoc.utils.input.createDay import be.vandewalleh.aoc.utils.input.createDay
import kotlin.math.pow import kotlin.math.pow
import org.eclipse.collections.impl.factory.primitive.IntObjectMaps import org.eclipse.collections.impl.factory.primitive.IntObjectMaps
import org.eclipse.collections.impl.factory.primitive.ObjectLongMaps import org.eclipse.collections.impl.factory.primitive.ObjectIntMaps
@Day(14) @Day(14)
class Day14(@Lines val input: Input<List<String>>) { class Day14(@Lines val input: Input<List<String>>) {
@ -42,48 +42,23 @@ class Day14(@Lines val input: Input<List<String>>) {
} }
fun part2(): Long { fun part2(): Long {
val mem = ObjectLongMaps.mutable.empty<String>() val mem = ObjectIntMaps.mutable.empty<String>()
var currentMask: String = "" var currentMask = ""
for (line in input.value) { for (line in input.value) {
if (line.startsWith("mask")) { if (line[1] == 'a') {
currentMask = line.removePrefix("mask = ") currentMask = line.substring(7)
} else { } else {
val (address, value) = memRe.find(line)!!.destructured.let { (add, value) -> val (address, value) = memRe.find(line)!!.destructured.let { (add, value) ->
add.toLong().toBin36() to value.toLong() add.toLong().toBin36() to value.toInt()
} }
val addresses = address.zip(currentMask).map { (address, mask) -> val builders = generateMutations(currentMask, address)
when (mask) {
'X' -> arrayOf('0', '1')
'1' -> arrayOf('1')
else -> arrayOf(address)
}
}
val mutations = currentMask.count { it == 'X' }.let { 2.0.pow(it.toDouble()).toInt() } for (builder in builders) {
val builders = Array(mutations) { StringBuilder() } mem.put(builder.toString(), value)
var groups = 1
for (address in addresses) {
if (address.size > 1) {
groups *= 2
val groupSize = mutations / groups
var j = 0
for (i in 0 until mutations) {
val flip = i % groupSize == 0
if (flip) j = if (j == 0) 1 else 0
builders[i].append(address[j])
}
} else {
builders.forEach { it.append(address[0]) }
}
}
builders.map { it.toString() }.forEach { address ->
mem.put(address, value)
} }
} }
} }
@ -91,6 +66,36 @@ class Day14(@Lines val input: Input<List<String>>) {
return mem.values().sum() return mem.values().sum()
} }
private fun generateMutations(mask: String, address: String): Array<StringBuilder> {
val mutations = mask.count { it == 'X' }.let { 2.0.pow(it.toDouble()).toInt() }
val builders = Array(mutations) { StringBuilder(36) }
var groups = 1
for (i in mask.indices) {
when (mask[i]) {
'X' -> {
groups *= 2
val groupSize = mutations / groups
var j = 1
for (b in builders.indices) {
val builder = builders[b]
val flip = b % groupSize == 0
if (flip) j = if (j == 0) 1 else 0
builder.append(j)
}
}
'1' -> {
builders.forEach { it.append('1') }
}
else -> {
builders.forEach { it.append(address[i]) }
}
}
}
return builders
}
} }
fun main() = with(createDay<Day14>()) { fun main() = with(createDay<Day14>()) {