2022/Day 14

Author: agrison

README.md

@@ -58,6 +58,10 @@
 🎄 ---- Day 13: Distress Signal ---
  🌟 Part 1: 5292 (43.82ms)
  🌟 Part 2: 23868 (8.9us) 
+ 
+🎄 ---- Day 14: Regolith Reservoir ---
+ 🌟 Part 1: 843 (255.6ms)
+ 🌟 Part 2: 27625 (8us) 
 ```
 
 ## Visualizations

src/main/kotlin/me/grison/aoc/Extensions.kt

@@ -403,4 +403,22 @@ fun Int.padLeft(length: Int, value: Char): String {
 
 fun Char.int() = this.toString().toInt()
 
-fun <T,U,V> t(t: T, u: U, v: V) = Triple(t, u, v)
+fun <T,U,V> t(t: T, u: U, v: V) = Triple(t, u, v)
+
+fun Position.sign() = p(first.sign(), second.sign())
+
+fun Position.x() = first
+fun Position.y() = second
+
+fun List<Int>.min() = minByOrNull { it }!!
+fun Iterable<Position>.minX() = map {it.first}.min()
+fun Iterable<Position>.minY() = map {it.second}.min()
+
+fun List<Int>.max() = maxByOrNull { it }!!
+fun Iterable<Position>.maxX() = map {it.first}.max()
+fun Iterable<Position>.maxY() = map {it.second}.max()
+
+fun <T> List<T>.peek(index: Int, sideEffect: (T) -> Unit) : List<T> {
+ sideEffect.invoke(this[index])
+ return this;
+}

src/main/kotlin/me/grison/aoc/y2022/Day14.kt

@@ -0,0 +1,63 @@
+package me.grison.aoc.y2022
+
+import arrow.syntax.function.memoize
+import me.grison.aoc.*
+
+class Day14 : Day(14, 2022) {
+ override fun title() = "Regolith Reservoir"
+
+ override fun partOne() = solve().first
+
+ override fun partTwo() = solve().second
+
+ private val solve = {
+ val filled = parse()
+
+ val floor = filled.maxY() + 2
+ fun canMove(sand: Position) =
+ sand.y() != floor && sand !in filled
+
+ var (part1, part2, tick) = listOf(-1, 0, 0)
+ while (true) {
+ var sand = p(500, 0)
+ while (true) {
+ if (sand.y() + 1 >= floor && part1 < 0)
+ part1 = tick
+
+ sand += when {
+ canMove(sand + p(0, 1)) -> p(0, 1)
+ canMove(sand + p(-1, 1)) -> p(-1, 1)
+ canMove(sand + p(1, 1)) -> p(1, 1)
+ else -> break
+ }
+ }
+
+ if (sand == p(500, 0)) {
+ part2 = tick + 1
+ break
+ }
+ filled.add(sand)
+ tick += 1
+ }
+
+ p(part1, part2)
+ }.memoize()
+
+ private fun parse() = mutableSetOf<Position>().let { filled ->
+ inputList.forEach { line ->
+ var last = p(-1, -1)
+ line.normalSplit(" -> ")
+ .map { it.allInts().pair() }
+ .forEach { pos ->
+ if (last == p(-1, -1)) {
+ filled.add(pos)
+ } else {
+ val diff = pos - last
+ filled.addAll((0..diff.abs().max()).map { p(it, it) * diff.sign() + last })
+ }
+ last = pos
+ }
+ }
+ filled
+ }
+}