2023 - Day11 - part 1 & 2

src/main/kotlin/no/rodland/advent/SpacePos.kt

@@ -193,6 +193,8 @@ data class Pos(val x: Int, val y: Int) : SpacePos(), Comparable<Pos> {
 
     operator fun minus(other: Pos): Pos = Pos(x - other.x, y - other.y)
 
+    fun manhattanDistance(p: Pos): Int = abs(x - p.x) + abs(y - p.y)
+
     operator fun plus(other: Pos): Pos = Pos(x + other.x, y + other.y)
     fun lineTo(other: Pos): List<Pos> {
         val xDelta = (other.x - x).sign

src/main/kotlin/no/rodland/advent_2023/Day11.kt

@@ -0,0 +1,67 @@
+package no.rodland.advent_2023
+
+import no.rodland.advent.Day
+import no.rodland.advent.Pos
+import kotlin.math.max
+import kotlin.math.min
+
+// template generated: 11/12/2023
+// Fredrik Rødland 2023
+
+class Day11(val input: List<String>) : Day<Long, Long, Set<Pos>> {
+
+    private val parsed = input.parse()
+
+    override fun partOne(): Long {
+        return findDistances(2)
+    }
+
+    override fun partTwo(): Long {
+        return findDistances(1000000)
+    }
+
+    private fun findDistances(expansion: Int): Long {
+        val maxX = input.maxOf { it.length }
+        val maxY = input.size
+        val missingCol = (0 until maxX) - parsed.map { it.x }.toSet()
+        val missingRow = (0 until maxY) - parsed.map { it.y }.toSet()
+        val pairs = parsed
+            .flatMap { pos1 ->
+                parsed.mapNotNull { pos2 ->
+                    if (pos1 != pos2) {
+                        if (pos1 < pos2) {
+                            pos1 to pos2
+                        } else {
+                            pos2 to pos1
+                        }
+                    } else {
+                        null
+                    }
+                }
+            }
+            .distinct()
+            .map { (from, to) ->
+                val distance = from.manhattanDistance(to)
+                val crossingCols = missingCol.count { it in (min(from.x, to.x)..max(to.x, from.x)) }
+                val crossingRows = missingRow.count { it in (min(from.y, to.y)..max(to.y, from.y)) }
+                (distance + (expansion - 1) * (crossingRows + crossingCols)).toLong()
+            }
+        return pairs.sum()
+    }
+
+
+    override fun List<String>.parse(): Set<Pos> {
+        val maxX = maxOf { it.length }
+        return indices.flatMap { y ->
+            (0 until maxX).mapNotNull { x ->
+                if (this[y][x] == '#') {
+                    Pos(x, y)
+                } else {
+                    null
+                }
+            }
+        }.toSet()
+    }
+
+    override val day = "11".toInt()
+}

src/test/kotlin/no/rodland/advent_2023/Day11Test.kt

@@ -0,0 +1,91 @@
+package no.rodland.advent_2023
+
+import no.rodland.advent.*
+import org.junit.jupiter.api.Nested
+import org.junit.jupiter.api.Test
+import readFile
+
+@Suppress("ClassName")
+@DisableSlow
+internal class Day11Test {
+    private val data11 = "2023/input_11.txt".readFile()
+    private val test11 = listOf(
+        "...#......",
+        ".......#..",
+        "#.........",
+        "..........",
+        "......#...",
+        ".#........",
+        ".........#",
+        "..........",
+        ".......#..",
+        "#...#.....",
+    )
+
+    private val resultTestOne = 374L
+    private val resultTestTwo = 82000210L
+    private val resultOne = 9805264L
+    private val resultTwo = 779032247216L
+
+    val test = defaultTestSuiteParseOnInit(
+        Day11(data11),
+        Day11(test11),
+        resultTestOne,
+        resultOne,
+        resultTestTwo,
+        resultTwo,
+        { Day11(data11) },
+        { Day11(test11) },
+        numTestPart1 = 5,
+        numTestPart2 = 5
+    )
+
+    @Nested
+    inner class Init {
+        @Test
+        fun `11,-,example,1`() {
+            report(AOCTest({ "123".toInt() }, Unit, 123, 5, "11".toInt(), Part.TWO, false, "example"))
+        }
+
+        @Test
+        fun `11,-,example,2`() {
+            report(test.initTest.copy())
+        }
+
+        @Test
+        fun `11,-,test,init`() {
+            report(test.initTest)
+        }
+
+        @Test
+        fun `11,-,live,init`() {
+            report(test.initLive)
+        }
+    }
+
+    @Nested
+    inner class `Part 1` {
+        @Test
+        fun `11,1,test`() {
+            report(test.testPart1)
+        }
+
+        @Test
+        fun `11,1,live,1`() {
+            report(test.livePart1)
+        }
+    }
+
+    @Nested
+    inner class `Part 2` {
+        @Test
+        fun `11,2,test`() {
+            report(test.testPart2)
+        }
+
+        @Test
+        fun `11,2,live,1`() {
+            report(test.livePart2)
+        }
+    }
+}