51 lines
1.6 KiB
Kotlin
51 lines
1.6 KiB
Kotlin
package be.vandewalleh.aoc.days
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import be.vandewalleh.aoc.utils.input.Day
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import be.vandewalleh.aoc.utils.input.Lines
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import org.eclipse.collections.api.factory.Stacks
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import org.eclipse.collections.api.multimap.list.ImmutableListMultimap
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import org.eclipse.collections.api.stack.MutableStack
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import org.eclipse.collections.impl.factory.Multimaps
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@Day(7)
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class Day07(@Lines val input: List<String>) {
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private data class Bag(val count: Int, val color: String)
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private val map: ImmutableListMultimap<String, Bag>
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init {
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val mutableMap = Multimaps.mutable.list.empty<String, Bag>()
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val colorRegex = "^(\\w+ \\w+)".toRegex()
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val requirementRegex = "(\\d+) (\\w+ \\w+) bag".toRegex()
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for (line in input) {
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val outerColor = colorRegex.find(line)!!.groupValues[1]
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for (match in requirementRegex.findAll(line)) {
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val (_, count, color) = match.groupValues
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mutableMap.put(outerColor, Bag(count.toInt(), color))
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}
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}
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map = mutableMap.toImmutable()
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}
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private fun bagSequence(rootColor: String): Sequence<Bag> = sequence {
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val stack: MutableStack<Bag> = Stacks.mutable.ofAll(map.get(rootColor))
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while (stack.notEmpty()) {
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val current = stack.pop().also { yield(it) }
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map[current.color]?.let {
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it.forEach { (count, color) ->
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stack.push(Bag(current.count * count, color))
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}
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}
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}
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}
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fun part1() = map.keySet().count { bagSequence(it).any { it.color == "shiny gold" } }
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fun part2() = bagSequence("shiny gold").sumBy { it.count }
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}
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