72 lines
2.0 KiB
Kotlin
72 lines
2.0 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.Input
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import be.vandewalleh.aoc.utils.input.Lines
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import be.vandewalleh.aoc.utils.input.createDay
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import org.eclipse.collections.impl.factory.primitive.IntLists
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import org.eclipse.collections.impl.factory.primitive.IntSets
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@Day(8)
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class Day08(@Lines val input: Input<List<String>>) {
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private val instructions = input.value
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.map {
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val words = it.split(" ")
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Instruction(Operation.valueOf(words[0].capitalize()), words[1].toInt())
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}.toTypedArray()
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fun part1() = run(instructions)
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private fun run(mutatedInstructions: Array<Instruction>): Int {
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var acc = 0
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var ptr = 0
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val visited = IntSets.mutable.empty()
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while (visited.add(ptr)) {
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val instruction = mutatedInstructions[ptr]
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when (instruction.operation) {
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Operation.Acc -> {
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acc += instruction.argument
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ptr++
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}
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Operation.Jmp -> ptr += instruction.argument
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Operation.Nop -> ptr++
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}
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if (ptr !in mutatedInstructions.indices) {
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println(acc)
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error("oob")
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}
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}
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return acc
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}
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fun part2() {
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val possibleMutations = IntLists.mutable.empty()
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instructions.forEachIndexed { i, e ->
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if (e.operation != Operation.Acc) possibleMutations.add(i)
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}
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possibleMutations.forEach { index ->
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val copy = instructions.clone().also {
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val modifiedOperation = if (it[index].operation == Operation.Nop) Operation.Jmp else Operation.Nop
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it[index] = it[index].copy(operation = modifiedOperation)
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}
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run(copy)
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}
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}
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}
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enum class Operation { Acc, Jmp, Nop }
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data class Instruction(val operation: Operation, val argument: Int)
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fun main() {
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val day = createDay<Day08>()
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println(day.part1())
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println(day.part2())
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}
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