Day 5: Print Queue
Megathread guidelines
- Keep top level comments as only solutions, if you want to say something other than a solution put it in a new post. (replies to comments can be whatever)
- You can send code in code blocks by using three backticks, the code, and then three backticks or use something such as https://topaz.github.io/paste/ if you prefer sending it through a URL
FAQ
- What is this?: Here is a post with a large amount of details: https://programming.dev/post/6637268
- Where do I participate?: https://adventofcode.com/
- Is there a leaderboard for the community?: We have a programming.dev leaderboard with the info on how to join in this post: https://programming.dev/post/6631465
You are viewing a single thread.
View all comments 
5 points
*
Kotlin
Took me a while to figure out how to sort according to the rules. 🤯
fun part1(input: String): Int {
val (rules, listOfNumbers) = parse(input)
return listOfNumbers
.filter { numbers -> numbers == sort(numbers, rules) }
.sumOf { numbers -> numbers[numbers.size / 2] }
}
fun part2(input: String): Int {
val (rules, listOfNumbers) = parse(input)
return listOfNumbers
.filterNot { numbers -> numbers == sort(numbers, rules) }
.map { numbers -> sort(numbers, rules) }
.sumOf { numbers -> numbers[numbers.size / 2] }
}
private fun sort(numbers: List<Int>, rules: List<Pair<Int, Int>>): List<Int> {
return numbers.sortedWith { a, b -> if (rules.contains(a to b)) -1 else 1 }
}
private fun parse(input: String): Pair<List<Pair<Int, Int>>, List<List<Int>>> {
val (rulesSection, numbersSection) = input.split("\n\n")
val rules = rulesSection.lines()
.mapNotNull { line -> """(\d{2})\|(\d{2})""".toRegex().matchEntire(line) }
.map { match -> match.groups[1]?.value?.toInt()!! to match.groups[2]?.value?.toInt()!! }
val numbers = numbersSection.lines().map { line -> line.split(',').map { it.toInt() } }
return rules to numbers
}
2 points
I guess adding type aliases and removing the regex from parser makes it a bit more readable.
typealias Rule = Pair<Int, Int>
typealias PageNumbers = List<Int>
fun part1(input: String): Int {
val (rules, listOfNumbers) = parse(input)
return listOfNumbers
.filter { numbers -> numbers == sort(numbers, rules) }
.sumOf { numbers -> numbers[numbers.size / 2] }
}
fun part2(input: String): Int {
val (rules, listOfNumbers) = parse(input)
return listOfNumbers
.filterNot { numbers -> numbers == sort(numbers, rules) }
.map { numbers -> sort(numbers, rules) }
.sumOf { numbers -> numbers[numbers.size / 2] }
}
private fun sort(numbers: PageNumbers, rules: List<Rule>): PageNumbers {
return numbers.sortedWith { a, b -> if (rules.contains(a to b)) -1 else 1 }
}
private fun parse(input: String): Pair<List<Rule>, List<PageNumbers>> {
val (rulesSection, numbersSection) = input.split("\n\n")
val rules = rulesSection.lines()
.mapNotNull { line ->
val parts = line.split('|').map { it.toInt() }
if (parts.size >= 2) parts[0] to parts[1] else null
}
val numbers = numbersSection.lines()
.map { line -> line.split(',').map { it.toInt() } }
return rules to numbers
}
1 point
