this post was submitted on 05 Dec 2024
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Advent Of Code

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๐Ÿ–จ๏ธ - 2024 DAY 5 SOLUTIONS - ๐Ÿ–จ๏ธ (self.advent_of_code)
submitted 2 weeks ago by CameronDev to c/advent_of_code
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Day 5: Print Queue

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[โ€“] proved_unglue 5 points 2 weeks ago* (last edited 2 weeks ago) (1 children)

Kotlin

Took me a while to figure out how to sort according to the rules. ๐Ÿคฏ

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
}
[โ€“] [email protected] 2 points 2 weeks ago (1 children)

I like how clean this is

[โ€“] proved_unglue 1 points 2 weeks ago (1 children)

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
}
[โ€“] [email protected] 1 points 2 weeks ago

I wasn't being sarcastic, but yeah even better