2024 day 01

advents/src/main/kotlin/net/fish/y2024/AdventOfCode.kt

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+@file:JvmName("AdventOfCode2024")
+package net.fish.y2024
+
+import net.fish.Reflect
+import net.fish.Runner
+
+object AdventOfCode {
+    val days = Reflect.getDays(2024)
+}
+
+fun main(args: Array<String>) {
+    // WindowsAnsi.setup()
+    val day = if(args.isEmpty()) 0 else args[0].toInt()
+    Runner.run(2024, AdventOfCode.days, day)
+}

advents/src/main/kotlin/net/fish/y2024/Day01.kt

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+package net.fish.y2024
+
+import kotlin.math.abs
+import net.fish.Day
+import net.fish.resourceLines
+
+object Day01 : Day {
+    private val data by lazy {
+        linesToLists(resourceLines(2024, 1))
+    }
+
+    override fun part1() = doPart1(data)
+    override fun part2() = doPart2(data)
+
+    fun doPart1(data: Pair<List<Int>, List<Int>>): Int = (data.first zip data.second).sumOf { (a, b) -> abs(a - b) }
+
+    fun doPart2(data: Pair<List<Int>, List<Int>>): Int {
+        val frequencies = data.second.groupingBy { it }.eachCount()
+        return data.first.sumOf { it * frequencies.getOrDefault(it, 0) }
+    }
+
+    private fun splitLine(line: String): Pair<Int, Int> = line.split("   ", limit = 2).map(String::toInt).let { (x, y) -> Pair(x, y) }
+
+    fun linesToLists(lines: List<String>): Pair<List<Int>, List<Int>> = lines
+        .map { splitLine(it) }
+        .fold(Pair(emptyList<Int>(), emptyList<Int>())) { acc, current ->
+            Pair(acc.first + current.first, acc.second + current.second)
+        }.let { (l1, l2) -> Pair(l1.sorted(), l2.sorted()) }
+
+    @JvmStatic
+    fun main(args: Array<String>) {
+        println(part1())
+        println(part2())
+    }
+}