Day 05 2025 (#299)

Author: peckb1

src/main/kotlin/me/peckb/aoc/_2025/calendar/day05/Day05.kt

@@ -0,0 +1,57 @@
+package me.peckb.aoc._2025.calendar.day05
+
+import javax.inject.Inject
+import me.peckb.aoc.generators.InputGenerator.InputGeneratorFactory
+import kotlin.math.max
+import kotlin.math.min
+
+class Day05 @Inject constructor(
+  private val generatorFactory: InputGeneratorFactory,
+) {
+  fun partOne(filename: String) = generatorFactory.forFile(filename).read { input ->
+    val (ranges, inventory) = parseInput(input)
+
+    inventory.count { ranges.any { r -> r.contains(it) } }
+  }
+
+  fun partTwo(filename: String) = generatorFactory.forFile(filename).read { input ->
+    val (ranges, _) = parseInput(input)
+
+    do {
+      val overlap = ranges.firstNotNullOfOrNull { r1 ->
+        ranges.firstOrNull { it != r1 && it.overlaps(r1) }?.let { it to r1 }
+      }
+
+      overlap?.let { (r1, r2) ->
+        ranges.remove(r1)
+        ranges.remove(r2)
+        ranges.add(min(r1.first, r2.first)..max(r1.last, r2.last))
+      }
+    } while (overlap != null)
+
+    ranges.distinct().sumOf { it.last - it.first + 1 }
+  }
+
+  private fun parseInput(input: Sequence<String>): Pair<MutableList<LongRange>, MutableList<Long>> {
+    val ranges = mutableListOf<LongRange>()
+    val inventory = mutableListOf<Long>()
+    var findingRanges = true
+    input.forEach { line ->
+      if (line.isEmpty()) {
+        findingRanges = false
+      } else {
+        if (findingRanges) {
+          line.split("-").let { (s, e) -> ranges.add(s.toLong()..e.toLong()) }
+        } else {
+          inventory.add(line.toLong())
+        }
+      }
+    }
+
+    return ranges to inventory
+  }
+
+  infix fun LongRange.overlaps(other: LongRange): Boolean {
+    return this.first <= other.last && other.first <= this.last
+  }
+}

src/main/kotlin/me/peckb/aoc/_2025/calendar/day05/README.md

@@ -0,0 +1 @@
+## [Day 5: Cafeteria](https://adventofcode.com/2025/day/5)

src/test/kotlin/me/peckb/aoc/_2025/TestDayComponent.kt

@@ -4,6 +4,7 @@ import dagger.Component
 import me.peckb.aoc._2025.calendar.day02.Day02Test
 import me.peckb.aoc._2025.calendar.day03.Day03Test
 import me.peckb.aoc._2025.calendar.day04.Day04Test
+import me.peckb.aoc._2025.calendar.day05.Day05Test
 import javax.inject.Singleton
 import me.peckb.aoc.DayComponent
 import me.peckb.aoc.InputModule
@@ -16,4 +17,5 @@ internal interface TestDayComponent : DayComponent {
   fun inject(day02Test: Day02Test)
   fun inject(day03Test: Day03Test)
   fun inject(day04Test: Day04Test)
+  fun inject(day05Test: Day05Test)
 }

src/test/kotlin/me/peckb/aoc/_2025/calendar/day05/Day05Test.kt

@@ -0,0 +1,32 @@
+package me.peckb.aoc._2025.calendar.day05
+
+import javax.inject.Inject
+
+import me.peckb.aoc._2025.DaggerTestDayComponent
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.BeforeEach
+import org.junit.jupiter.api.Test
+
+internal class Day05Test {
+  @Inject
+  lateinit var day05: Day05
+
+  @BeforeEach
+  fun setup() {
+    DaggerTestDayComponent.create().inject(this)
+  }
+
+  @Test
+  fun testDay05PartOne() {
+    assertEquals(798, day05.partOne(DAY_05))
+  }
+
+  @Test
+  fun testDay05PartTwo() {
+    assertEquals(366181852921027, day05.partTwo(DAY_05))
+  }
+
+  companion object {
+    private const val DAY_05: String = "advent-of-code-input/2025/day05.input"
+  }
+}