Day 5: Print Queue

README.md

@@ -9,4 +9,4 @@ Development occurs in language-specific directories:
 |[Day2.hs](hs/src/Day2.hs)|[Day2.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day2.kt)|[day2.py](py/aoc2024/day2.py)|[day2.rs](rs/src/day2.rs)|
 |[Day3.hs](hs/src/Day3.hs)|[Day3.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day3.kt)|[day3.py](py/aoc2024/day3.py)|[day3.rs](rs/src/day3.rs)|
 |[Day4.hs](hs/src/Day4.hs)|[Day4.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day4.kt)|[day4.py](py/aoc2024/day4.py)|[day4.rs](rs/src/day4.rs)|
-|[Day5.hs](hs/src/Day5.hs)||||
+|[Day5.hs](hs/src/Day5.hs)|[Day5.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day5.kt)|||

kt/aoc2024-exe/src/commonBench/kotlin/com/github/ephemient/aoc2024/exe/Day5Bench.kt

@@ -0,0 +1,23 @@
+package com.github.ephemient.aoc2024.exe
+
+import com.github.ephemient.aoc2024.Day5
+import kotlinx.benchmark.Benchmark
+import kotlinx.benchmark.Scope
+import kotlinx.benchmark.Setup
+import kotlinx.benchmark.State
+
+@State(Scope.Benchmark)
+class Day5Bench {
+    private lateinit var input: String
+
+    @Setup
+    fun setup() {
+        input = getDayInput(5)
+    }
+
+    @Benchmark
+    fun part1() = Day5(input).part1()
+
+    @Benchmark
+    fun part2() = Day5(input).part2()
+}

kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day5.kt

@@ -0,0 +1,40 @@
+package com.github.ephemient.aoc2024
+
+class Day5(input: String) {
+    private val deps: Set<IntPair>
+    private val updates: List<List<Int>>
+
+    init {
+        val (deps, updates) = input.split("\n\n")
+        this.deps = deps.lines().mapTo(mutableSetOf()) { line ->
+            val (first, second) = line.split('|', limit = 2)
+            first.toInt() to second.toInt()
+        }
+        this.updates = updates.lines().mapNotNull { line ->
+            line.ifEmpty { return@mapNotNull null }.split(',').map { it.toInt() }
+        }
+    }
+
+    fun part1() = updates.sumOf { pages ->
+        if (
+            pages.withIndex().all { (i, x) ->
+                pages.subList(i + 1, pages.size).all { y -> y to x !in deps }
+            }
+        ) pages[pages.size / 2] else 0
+    }
+
+    fun part2(): Int = updates.sumOf { update ->
+        val pages = update.toMutableList()
+        for (i in pages.indices) {
+            while (true) {
+                val x = pages[i]
+                val j = i + 1 + pages.subList(i + 1, pages.size).indexOfFirst { it to x in deps }
+                if (j > i) {
+                    pages[i] = pages[j]
+                    pages[j] = x
+                } else break
+            }
+        }
+        if (update != pages) pages[pages.size / 2] else 0
+    }
+}

kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Days.kt

@@ -5,6 +5,7 @@ val days: List<Day> = listOf(
     Day(2, ::Day2, Day2::part1, Day2::part2),
     Day(3, ::Day3, Day3::part1, Day3::part2),
     Day(4, ::Day4, Day4::part1, Day4::part2),
+    Day(5, ::Day5, Day5::part1, Day5::part2),
 )
 
 data class Day(

kt/aoc2024-lib/src/commonTest/kotlin/com/github/ephemient/aoc2024/Day5Test.kt

@@ -0,0 +1,50 @@
+package com.github.ephemient.aoc2024
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class Day5Test {
+    @Test
+    fun part1() {
+        assertEquals(143, Day5(example).part1())
+    }
+
+    @Test
+    fun part2() {
+        assertEquals(123, Day5(example).part2())
+    }
+
+    companion object {
+        private val example =
+            """
+            |47|53
+            |97|13
+            |97|61
+            |97|47
+            |75|29
+            |61|13
+            |75|53
+            |29|13
+            |97|29
+            |53|29
+            |61|53
+            |97|53
+            |61|29
+            |47|13
+            |75|47
+            |97|75
+            |47|61
+            |75|61
+            |47|29
+            |75|13
+            |53|13
+            |
+            |75,47,61,53,29
+            |97,61,53,29,13
+            |75,29,13
+            |75,97,47,61,53
+            |61,13,29
+            |97,13,75,29,47
+            |""".trimMargin()
+    }
+}