Merge pull request #138 from ephemient/kt/day21

README.md

@@ -25,4 +25,4 @@ Development occurs in language-specific directories:
 |[Day18.hs](hs/src/Day18.hs)|[Day18.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day18.kt)|[day18.py](py/aoc2024/day18.py)|[day18.rs](rs/src/day18.rs)|
 |[Day19.hs](hs/src/Day19.hs)|[Day19.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day19.kt)|[day19.py](py/aoc2024/day19.py)|[day19.rs](rs/src/day19.rs)|
 |[Day20.hs](hs/src/Day20.hs)|[Day20.kt](kt/aoc2024-lib/src/commonMain/kotlin/com/github/ephemient/aoc2024/Day20.kt)|[day20.py](py/aoc2024/day20.py)|[day20.rs](rs/src/day20.rs)|
-|[Day21.hs](hs/src/Day21.hs)||||
+|[Day21.hs](hs/src/Day21.hs)|[Day21.kt](kt/aoc2024-lib/src/jvmCodegen/kotlin/com/github/ephemient/aoc2024/codegen/Day21.kt)|||

kt/aoc2024-exe/src/commonBench/kotlin/com/github/ephemient/aoc2024/exe/Day21Bench.kt

@@ -0,0 +1,31 @@
+package com.github.ephemient.aoc2024.exe
+
+import com.github.ephemient.aoc2024.Day21
+import kotlinx.benchmark.Benchmark
+import kotlinx.benchmark.Blackhole
+import kotlinx.benchmark.Scope
+import kotlinx.benchmark.Setup
+import kotlinx.benchmark.State
+
+@State(Scope.Benchmark)
+class Day21Bench {
+    private lateinit var input: String
+
+    @Setup
+    fun setup() {
+        input = getDayInput(21)
+    }
+
+    @Benchmark
+    fun part1() = Day21(input).part1()
+
+    @Benchmark
+    fun part2() = Day21(input).part2()
+
+    @Benchmark
+    fun solve(bh: Blackhole) {
+        val day21 = Day21(input)
+        bh.consume(day21.part1())
+        bh.consume(day21.part2())
+    }
+}

kt/aoc2024-lib/build.gradle.kts

@@ -4,7 +4,16 @@ plugins {
 }
 
 kotlin {
-    jvm()
+    jvm {
+        val codegen by compilations.creating
+        val runCodegen by tasks.registering(JavaExec::class) {
+            mainClass = "com.github.ephemient.aoc2024.codegen.Main"
+            classpath(codegen.output.allOutputs, codegen.runtimeDependencyFiles)
+            outputs.dir(layout.buildDirectory.dir("build/sources/codegen"))
+            argumentProviders.add { listOf(outputs.files.singleFile.path) }
+        }
+        kotlin.sourceSets.getByName("commonMain").kotlin.srcDirs(runCodegen)
+    }
     wasmJs {
         browser()
         nodejs()
@@ -54,6 +63,12 @@ kotlin {
                 runtimeOnly(libs.junit.jupiter.engine)
             }
         }
+
+        getByName("jvmCodegen") {
+            dependencies {
+                implementation(libs.kotlinpoet)
+            }
+        }
     }
 
     val detektTaskNames = targets.flatMap { target ->

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

@@ -21,6 +21,7 @@ val days: List<Day> = listOf(
     Day(18, ::Day18, Day18::part1, Day18::part2),
     Day(19, ::Day19, Day19::solve),
     Day(20, ::Day20, Day20::part1, Day20::part2),
+    Day(21, ::Day21, Day21::part1, Day21::part2),
 )
 
 data class Day(

kt/aoc2024-lib/src/commonTest/kotlin/com/github/ephemient/aoc2024/Day21Test.kt

@@ -0,0 +1,22 @@
+package com.github.ephemient.aoc2024
+
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+class Day21Test {
+    @Test
+    fun part1() {
+        assertEquals(126384, Day21(example).part1())
+    }
+
+    companion object {
+        private val example =
+            """
+            |029A
+            |980A
+            |179A
+            |456A
+            |379A
+            |""".trimMargin()
+    }
+}

kt/aoc2024-lib/src/jvmCodegen/kotlin/com/github/ephemient/aoc2024/codegen/Day21.kt

@@ -0,0 +1,141 @@
+package com.github.ephemient.aoc2024.codegen
+
+import com.squareup.kotlinpoet.ClassName
+import com.squareup.kotlinpoet.CodeBlock
+import com.squareup.kotlinpoet.FileSpec
+import com.squareup.kotlinpoet.FunSpec
+import com.squareup.kotlinpoet.KModifier
+import com.squareup.kotlinpoet.LIST
+import com.squareup.kotlinpoet.LONG
+import com.squareup.kotlinpoet.LONG_ARRAY
+import com.squareup.kotlinpoet.MemberName
+import com.squareup.kotlinpoet.MemberName.Companion.member
+import com.squareup.kotlinpoet.ParameterizedTypeName.Companion.parameterizedBy
+import com.squareup.kotlinpoet.PropertySpec
+import com.squareup.kotlinpoet.STRING
+import com.squareup.kotlinpoet.TypeSpec
+import com.squareup.kotlinpoet.joinToCode
+import java.nio.file.Path
+import kotlin.math.abs
+
+fun day21(outputDir: Path, className: ClassName = ClassName("com.github.ephemient.aoc2024", "Day21")) {
+    FileSpec.builder(className)
+        .addType(
+            TypeSpec.classBuilder(className)
+                .primaryConstructor(
+                    FunSpec.constructorBuilder()
+                        .addParameter("input", STRING)
+                        .build()
+                )
+                .addProperty(
+                    PropertySpec.builder("lines", LIST.parameterizedBy(STRING))
+                        .addModifiers(KModifier.PRIVATE)
+                        .initializer("%N.%M()", "input", MemberName("kotlin.text", "lines"))
+                        .build()
+                )
+                .addFunctions(
+                    arrayOf(IndexedValue(2, "part1"), IndexedValue(25, "part2")).map { (depth, name) ->
+                        FunSpec.builder(name)
+                            .returns(LONG)
+                            .beginControlFlow("return %N.%M", "lines", MemberName("kotlin.collections", "sumOf"))
+                            .addStatement("var %N = 10", "i")
+                            .addStatement("var %N = 0", "numeric")
+                            .addStatement("var %N = 0L", "length")
+                            .beginControlFlow("for (%N in %N)", "char", "it")
+                            .beginControlFlow("val %N = when (%N)", "j", "char")
+                            .beginControlFlow("in '0'..'9' ->")
+                            .addStatement("%1N = 10 * %1N + (%2N - '0')", "numeric", "char")
+                            .addStatement("%N - '0'", "char")
+                            .endControlFlow()
+                            .addStatement("else -> 10")
+                            .endControlFlow()
+                            .addStatement(
+                                "%N += %M[11 * %N + %N]",
+                                "length",
+                                className.nestedClass("Companion").member(name),
+                                "i",
+                                "j",
+                            )
+                            .addStatement("%N = %N", "i", "j")
+                            .endControlFlow()
+                            .addStatement("%N * %N", "numeric", "length")
+                            .endControlFlow()
+                            .build()
+                    }
+                )
+                .addType(
+                    TypeSpec.companionObjectBuilder()
+                        .addProperty(
+                            PropertySpec.builder("part1", LONG_ARRAY)
+                                .addModifiers(KModifier.PRIVATE)
+                                .initializer(
+                                    "%M(%L)",
+                                    MemberName("kotlin", "longArrayOf"),
+                                    lut(2).joinToCode(",♢") { CodeBlock.of("%L", it) },
+                                )
+                                .build()
+                        )
+                        .addProperty(
+                            PropertySpec.builder("part2", LONG_ARRAY)
+                                .addModifiers(KModifier.PRIVATE)
+                                .initializer(
+                                    "%M(%L)",
+                                    MemberName("kotlin", "longArrayOf"),
+                                    lut(25).joinToCode(",♢") { CodeBlock.of("%L", it) },
+                                )
+                                .build()
+                        )
+                        .build()
+                )
+                .build()
+        )
+        .build()
+        .writeTo(outputDir)
+}
+
+private val keypad = intArrayOf(
+    3 * 1 + 1, // 0
+    3 * 2 + 0, // 1
+    3 * 2 + 1, // 2
+    3 * 2 + 2, // 3
+    3 * 3 + 0, // 4
+    3 * 3 + 1, // 5
+    3 * 3 + 2, // 6
+    3 * 4 + 0, // 7
+    3 * 4 + 1, // 8
+    3 * 4 + 2, // 9
+    3 * 1 + 2, // A
+)
+private const val BLANK = 3 * 1 + 0
+private const val UP = 3 * 1 + 1
+private const val A = 3 * 1 + 2
+private const val LEFT = 3 * 0 + 0
+private const val DOWN = 3 * 0 + 1
+private const val RIGHT = 3 * 0 + 2
+
+private fun lut(depth: Int): List<Long> {
+    var lut = Array(15 * 15) {
+        val p1 = it / 15
+        val p2 = it % 15
+        if (p1 == BLANK || p2 == BLANK) null else abs(p2 / 3 - p1 / 3) + abs(p2 % 3 - p1 % 3) + 1L
+    }
+    fun best(p1: Int, p2: Int, pos: Int): Long? {
+        if (p1 == BLANK || p2 == BLANK) return null
+        if (p1 == p2) return lut[15 * pos + A]
+        val v = when {
+            p1 / 3 < p2 / 3 -> lut[15 * pos + UP]?.let { best(p1 + 3, p2, UP)?.let(it::plus) }
+            p1 / 3 > p2 / 3 -> lut[15 * pos + DOWN]?.let { best(p1 - 3, p2, DOWN)?.let(it::plus) }
+            else -> null
+        }
+        val h = when {
+            p1 % 3 < p2 % 3 -> lut[15 * pos + RIGHT]?.let { best(p1 + 1, p2, RIGHT)?.let(it::plus) }
+            p1 % 3 > p2 % 3 -> lut[15 * pos + LEFT]?.let { best(p1 - 1, p2, LEFT)?.let(it::plus) }
+            else -> null
+        }
+        return if (v != null && h != null) minOf(v, h) else v ?: h
+    }
+    repeat(depth) { lut = Array(15 * 15) { best(it / 15, it % 15, A) } }
+    return List(11 * 11) { lut[15 * keypad[it / 11] + keypad[it % 11]]!! }.also {
+        println(it.chunked(11).joinToString(",\n", "Day21[$depth] = [\n", "]") { it.joinToString() })
+    }
+}

kt/aoc2024-lib/src/jvmCodegen/kotlin/com/github/ephemient/aoc2024/codegen/Main.kt

@@ -0,0 +1,16 @@
+@file:JvmName("Main")
+
+package com.github.ephemient.aoc2024.codegen
+
+import java.nio.file.Files
+import kotlin.io.path.ExperimentalPathApi
+import kotlin.io.path.Path
+import kotlin.io.path.deleteRecursively
+
+@OptIn(ExperimentalPathApi::class)
+fun main(argv: Array<String>) {
+    val outputDir = Path(argv.single())
+    outputDir.deleteRecursively()
+    Files.createDirectory(outputDir)
+    day21(outputDir)
+}

kt/gradle/libs.versions.toml

@@ -4,6 +4,7 @@ junit-jupiter = "5.11.4"
 kotlin = "2.1.0"
 kotlinx-benchmark = "0.4.13"
 kotlinx-coroutines = "1.10.1"
+kotlinpoet = "2.0.0"
 native-image = "0.10.4"
 okio = "3.9.1"
 
@@ -19,6 +20,7 @@ detekt-formatting = { module = "io.gitlab.arturbosch.detekt:detekt-formatting",
 junit-jupiter-api = { module = "org.junit.jupiter:junit-jupiter-api", version.ref = "junit-jupiter" }
 junit-jupiter-engine = { module = "org.junit.jupiter:junit-jupiter-engine", version.ref = "junit-jupiter" }
 kotlin-wrappers-node = { module = "org.jetbrains.kotlin-wrappers:kotlin-node", version = "22.5.5-pre.854" }
+kotlinpoet = { module = "com.squareup:kotlinpoet", version.ref = "kotlinpoet" }
 kotlinx-benchmark = { module = "org.jetbrains.kotlinx:kotlinx-benchmark-runtime", version.ref = "kotlinx-benchmark" }
 kotlinx-coroutines = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-core", version.ref = "kotlinx-coroutines" }
 kotlinx-coroutines-test = { module = "org.jetbrains.kotlinx:kotlinx-coroutines-test", version.ref = "kotlinx-coroutines" }