2024 Day 09 Part 1

Author: fibsifan

src/main/kotlin/de/jball/aoc2024/day09/Day09.kt

@@ -0,0 +1,37 @@
+package de.jball.aoc2024.day09
+
+import de.jball.AdventOfCodeDay
+
+class Day09(test: Boolean = false): AdventOfCodeDay<Long>(test, 1928, 0) {
+	val fileDb = input[0].windowed(2, 2, partialWindows = true).flatMapIndexed { index, blocks ->
+		val fileSize = blocks.first().toString().toInt()
+		val gapSize = if (blocks.length > 1) blocks.last().toString().toInt() else 0
+		val file = List<Long?>(fileSize) { index.toLong() }
+		val gap = List<Long?>(gapSize) { null }
+		file + gap
+	}.toMutableList()
+
+	override fun part1(): Long {
+		var currentGap = fileDb.indexOfFirst { it == null }
+		var lastValue = fileDb.indexOfLast { it != null }
+
+		while(currentGap < lastValue) {
+			fileDb[currentGap] = fileDb[lastValue]
+			fileDb[lastValue] = null
+			currentGap = fileDb.indexOfFirst { it == null }
+			lastValue = fileDb.indexOfLast { it != null }
+		}
+		return fileDb.filter { it != null }
+			.mapIndexed { index, entry ->
+				index.toLong() * entry!!
+			}.sum()
+	}
+
+	override fun part2(): Long {
+		TODO("Not yet implemented")
+	}
+}
+
+fun main() {
+	Day09().run()
+}

src/test/kotlin/de/jball/aoc2024/Tests2024.kt

@@ -8,6 +8,7 @@ import de.jball.aoc2024.day05.Day05
 import de.jball.aoc2024.day06.Day06
 import de.jball.aoc2024.day07.Day07
 import de.jball.aoc2024.day08.Day08
+import de.jball.aoc2024.day09.Day09
 import kotlin.test.Test
 
 class Tests2024 {
@@ -50,4 +51,9 @@ class Tests2024 {
 	fun day08() {
 		Day08(true).run()
 	}
+
+	@Test
+	fun day09() {
+		Day09(true).run()
+	}
 }

src/test/resources/2024/Day09.txt

@@ -0,0 +1 @@
+2333133121414131402