Prepare for 2018-17 (Reservoir Research)

* implement a map-backed char grid
* parse the input to the grid

Author: rhaendel

src/main/kotlin/de/ronny_h/aoc/year2018/day17/ReservoirResearch.kt

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+package de.ronny_h.aoc.year2018.day17
+
+import de.ronny_h.aoc.AdventOfCode
+import de.ronny_h.aoc.extensions.grids.Coordinates
+import java.io.ByteArrayOutputStream
+import java.io.PrintStream
+import kotlin.math.max
+import kotlin.math.min
+import kotlin.text.Charsets.UTF_8
+
+fun main() = ReservoirResearch().run(0, 0)
+
+class ReservoirResearch : AdventOfCode<Int>(2018, 17) {
+    override fun part1(input: List<String>): Int {
+        return 0
+    }
+
+    override fun part2(input: List<String>): Int {
+        return 0
+    }
+}
+
+class VerticalSliceOfGround(input: List<String>) {
+    private val clay = '#'
+    private val sand = '.'
+    private val waterSpring = '+'
+
+    private val slice = MapBackedCharGrid(Coordinates(500, 0), sand)
+
+    init {
+        slice[Coordinates(500, 0)] = waterSpring
+        input.forEach {
+            val (single, range) = it.split(", ")
+            if (single.startsWith('x')) {
+                slice[single.intAfter("x="), range.intRangeAfter("y=")] = clay
+            } else {
+                slice[range.intRangeAfter("x="), single.intAfter("y=")] = clay
+            }
+        }
+    }
+
+    override fun toString(): String = slice.toString()
+
+    private fun String.intAfter(delimiter: String): Int = substringAfter(delimiter).toInt()
+
+    private fun String.intRangeAfter(delimiter: String): IntRange {
+        val (from, to) = substringAfter(delimiter).split("..").map(String::toInt)
+        return from..to
+    }
+}
+
+class MapBackedCharGrid(center: Coordinates, default: Char) {
+    private var minX = center.x
+    private var maxX = center.x
+    private var minY = center.y
+    private var maxY = center.y
+
+    private val slice = mutableMapOf<Coordinates, Char>().withDefault { default }
+
+    operator fun set(position: Coordinates, value: Char) {
+        minX = min(minX, position.x)
+        minY = min(minY, position.y)
+        maxX = max(maxX, position.x)
+        maxY = max(maxY, position.y)
+        slice[position] = value
+    }
+
+    operator fun set(x: Int, y: Int, value: Char) = set(Coordinates(x, y), value)
+
+    operator fun get(position: Coordinates) = slice.getValue(position)
+
+    operator fun set(x: Int, yRange: IntRange, value: Char) {
+        for (y in yRange) {
+            this[Coordinates(x, y)] = value
+        }
+    }
+
+    operator fun set(xRange: IntRange, y: Int, value: Char) {
+        for (x in xRange) {
+            this[Coordinates(x, y)] = value
+        }
+    }
+
+    override fun toString(): String {
+        val out = ByteArrayOutputStream()
+        PrintStream(out, true, UTF_8).use {
+            for (y in minY..maxY) {
+                for (x in minX - 1..maxX + 1) {
+                    it.print(this[Coordinates(x, y)])
+                }
+                it.print('\n')
+            }
+        }
+        return out.toString(UTF_8).trim()
+    }
+}

src/test/kotlin/de/ronny_h/aoc/year2018/day17/ReservoirResearchTest.kt

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+package de.ronny_h.aoc.year2018.day17
+
+import de.ronny_h.aoc.extensions.asList
+import io.kotest.core.spec.style.StringSpec
+import io.kotest.matchers.shouldBe
+
+class ReservoirResearchTest : StringSpec({
+
+    val input = """
+        x=495, y=2..7
+        y=7, x=495..501
+        x=501, y=3..7
+        x=498, y=2..4
+        x=506, y=1..2
+        x=498, y=10..13
+        x=504, y=10..13
+        y=13, x=498..504
+    """.asList()
+
+    "input can be parsed" {
+        val expectedSlice = """
+            ......+.......
+            ............#.
+            .#..#.......#.
+            .#..#..#......
+            .#..#..#......
+            .#.....#......
+            .#.....#......
+            .#######......
+            ..............
+            ..............
+            ....#.....#...
+            ....#.....#...
+            ....#.....#...
+            ....#######...
+        """.trimIndent()
+        VerticalSliceOfGround(input).toString() shouldBe expectedSlice
+    }
+
+    "part 1" {
+        val input = listOf("")
+        ReservoirResearch().part1(input) shouldBe 0
+    }
+
+    "part 2" {
+        val input = listOf("")
+        ReservoirResearch().part2(input) shouldBe 0
+    }
+})