2022/Day 07

Author: agrison

README.md

@@ -26,6 +26,15 @@
 🎄 --- Day 5: Supply Stacks ---
  🌟 Part 1: MQTPGLLDN (7.32ms)
  🌟 Part 2: LVZPSTTCZ (4.71ms) 
+ 
+🎄 --- Day 6: Tuning Trouble ---
+ 🌟 Part 1: 1080 (9.47ms)
+ 🌟 Part 2: 3645 (4.73ms) 
+ 
+🎄 --- Day 7: No Space Left On Device ---
+ 🌟 Part 1: 1582412 (11.92ms)
+ 🌟 Part 2: 3696336 (74.4us)
+ 
 ```
 
 ## Visualizations

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

@@ -94,6 +94,12 @@ fun <T> List<List<T>>.transpose(): List<List<T>> {
  .toList()
 }
 
+fun <T> MutableList<T>.reset(item: T) : MutableList<T> {
+ this.clear()
+ this.add(item)
+ return this
+}
+
 /** Make an ArrayDeque representing this Collection. */
 fun <T> Collection<T>.deque() = ArrayDeque(this)
 

src/main/kotlin/me/grison/aoc/y2022/Day07.kt

@@ -0,0 +1,37 @@
+package me.grison.aoc.y2022
+
+import arrow.syntax.function.memoize
+import me.grison.aoc.*
+
+class Day07 : Day(7, 2022) {
+ override fun title() = "No Space Left On Device"
+
+ override fun partOne() = disk().values.filter { it <= 100000 }.sum()
+
+ override fun partTwo() = (70000000 - disk().getValue("/<root>")).let { emptySpace ->
+ disk().values.filter { emptySpace + it > 30000000 }.minOrNull()
+ }
+
+ private val disk = {
+ val directorySizes = mutableMapOf<String, Int>().withDefault { 0 }
+ val currentPath = mutableListOf<String>()
+ inputList
+ .filter { !it.startsWith("dir ") }
+ .map { ("$it #").words() }
+ .forEach { (promptOrSize, commandOrName, cdPath) ->
+ when (promptOrSize) {
+ "$" -> when (commandOrName) {
+ "cd" -> when (cdPath) {
+ "/" -> currentPath.reset("<root>")
+ ".." -> currentPath.removeLast()
+ else -> currentPath.append(cdPath)
+ }
+ }
+ else -> currentPath.scan("") { acc, dir -> "$acc/$dir" }.forEach { fullPath ->
+ directorySizes.increase(fullPath, promptOrSize.toInt())
+ }
+ }
+ }
+ directorySizes
+ }.memoize()
+}