2022/Day 12

Author: agrison

README.md

@@ -50,6 +50,10 @@
 🎄 ---- Day 11: Monkey in the Middle ---
  🌟 Part 1: 76728 (30.8ms)
  🌟 Part 2: 21553910156 (100.1ms) 
+ 
+🎄 ---- Day 12: Hill Climbing Algorithm ---
+ 🌟 Part 1: 391 (21.16ms)
+ 🌟 Part 2: 386 (237.14ms)
 ```
 
 ## Visualizations

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

@@ -41,7 +41,7 @@ fun <T> Graph<T>.shortestPath(a: T, b: T): Pair<Int, List<T>> {
  val (node, distance, path) = queue.shift()
  if (b == node) return p(distance, path)
 
- for (neighbor in this[node]!!) {
+ for (neighbor in (this[node] ?: listOf())) {
  if (neighbor !in visited) {
  visited.add(neighbor)
  val newPath = path.toMutableList() + neighbor

src/main/kotlin/me/grison/aoc/y2022/Day12.kt

@@ -0,0 +1,32 @@
+package me.grison.aoc.y2022
+
+import me.grison.aoc.*
+
+class Day12 : Day(12, 2022) {
+ override fun title() = "Hill Climbing Algorithm"
+
+ private fun cellValue(x: String) =
+ x.replace("S", "a").replace("E", "z").first().code
+
+ override fun partOne() = solve("S")
+
+ override fun partTwo() = solve("a")
+
+ private fun solve(start: String): Int {
+ val grid = inputList.stringGrid("z")
+ val starts = grid.allPositions().filter { grid.at(it) == start }
+ val end = grid.allPositions().find { grid.at(it) == "E" }!!
+
+ val edges = mutableListOf<Pair<Position, Position>>()
+ grid.allPositions().forEach { p ->
+ for (dir in p.directions()) {
+ if (cellValue(grid.at(dir)) <= cellValue(grid.at(p)) + 1) {
+ edges.add(p(p, dir))
+ }
+ }
+ }
+
+ val graph = edges.toDirectedGraph()
+ return starts.map { graph.shortestPath(it, end).first }.filter { it > -1 }.minOrNull()!!
+ }
+}

src/main/resources/2022/12.txt

@@ -0,0 +1,41 @@
+abaccccccccccccccaaaccccaaaaaaaaaaaaaccccccaacccccccccccccccccccccccccccccaaaaaa
+abaaccaacccccccccaaaaaccccaaaaaaaaaaaaaccccaaacccccccccccccccccccccccccccccaaaaa
+abaaccaaacccccccaaaaaacccaaaaaaaaaaaaaacaaaaaaaaccccccccaacccccccccccccccccccaaa
+abcaaaaaaaacccccaaaaaacccaaaaaaaaaaaaaacaaaaaaaacccccccaaaacccccccccccccccccaaaa
+abcaaaaaaaaccccccaaaaaccaaaaaaaaccaaaaaccaaaaaaccccccccaaaaccaaaccccccccccccaaac
+abccaaaaaacccccccaaaaccaaaaaaaaaacaaaacccaaaaaacccccccccakkaaaaaacccccccccccaacc
+abccaaaaaacccccccccccccaaaaaaaaaaccccccccaaaaaaccccccckkkkkkkaaacccccccccccccccc
+abccaaaaaaccccccccccccccccaaaaaaaaaccccccaacaaacccccckkkkkkkkkaccccccaccaaaccccc
+abccaacaaacccccaaccccccccaaacacaaaacaaccccccccccccccakkkoppkkkkicccccaaaaaaccccc
+abccccccccccccaaaccccccccaacccccaaaaaaccccccccccccccjkkooppppkiicccccccaaaaccccc
+abccccccccccaaaaaaaaccccccccccaaaaaaaccccccccccccccjjjooopppppiiiicccccccaaacccc
+abaaacccccccaaaaaaaacccccccaacaaaaaaccccccccccccccjjjjooouuppppiiiiiicccccaacccc
+abaaaccccccccaaaaaaccccccccaaaccaaaaacccccccccccjjjjjooouuuupppiiiiiiiiccccacccc
+abaaaaaacccccaaaaaacccccaaaaaaaaaacaaaccccccccjjjjjjooouuuuuupppppiiiiiicccccccc
+abaaaaaacccccaaaaaacccccaaaaaaaaaacccccccccccjjjjjooooouuxxuupppppqqqijjjccccccc
+abaaaacccccaaaaccaaccccccaaaaaaccccccccccccciijjnooooouuuxxxuuupqqqqqqjjjdddcccc
+abaaaaaccaaaaaaccacccccccaaaaaaccccccccccaaiiiinnootttuuxxxxuuvvvvvqqqjjjdddcccc
+abaaaaaccaaaaaacaaaccaaccaaaaaaccccccccccaaiiinnnntttttuxxxxxvvvvvvqqqjjjdddcccc
+abaaccacccaaaaacaaaaaaaccaaccaaccccccccccaaiiinnnttttxxxxxxxyyyyyvvqqqjjjdddcccc
+abcccccccaaaaacccaaaaaaccccccaaaaacccccccaaiiinnntttxxxxxxxyyyyyvvvqqqjjjddccccc
+SbcccccccaaaaacaaaaaaaaccccccaaaaaccccccccciiinnntttxxxEzzzzyyyyvvqqqjjjdddccccc
+abcccccccccccccaaaaaaaaaccccaaaaaaccccccccciiinnnntttxxxxyyyyyvvvvqqjjjdddcccccc
+abcccccccccccccaaaaaaaaaacccaaaaaacccccccccciiinnnttttxxxyyyyyvvvqqqjjjdddcccccc
+abccccccccccccccccaaaaaaacccaaaaaaccccccccccciiinnnntttwyyywyyyvvrrrkkjdddcccccc
+abcccccccccccccccaaaaaaaaccccaaaccccccccccccciiihnnnttwwwywwyyywvrrrkkkeeccccccc
+abcccccccccccccccaaaaaaaaccccccccccccccccccccchhhmmmsswwwwwwwwwwwvrrkkkeeccccccc
+abcccccccaacccccccacaaacccccccccccccccccccaacchhhhmmsswwwwwswwwwwrrrkkkeeccccccc
+abcccccccaaaccacccccaaacccccccccccccccaaccaaccchhhmmssswwwssrrwwwrrrkkkeeccccccc
+abcccccccaaaaaaacccccccccccaaaccccccccaaaaaaccchhhmmssssssssrrrrrrrrkkkeeaaacccc
+abcccccaaaaaaaaccccccccccccaaaaccccccccaaaaaaachhhmmmssssssllrrrrrrkkkeeeaaacccc
+abccccaaaaaaaaaccccccccccccaaaacccccccccaaaaacchhhmmmmsssllllllllkkkkkeeeaaacccc
+abccccaaaaaaaaaccccccccccccaaacccccccccaaaaacccchhhmmmmmlllllllllkkkkeeeeaaccccc
+abcccccccaaaaaaccccccccccaacccccccaaccaaacaacccchhhmmmmmlllgfflllkkffeeeaaaacccc
+abccccccaaaaaaaccccccccccaaaaaaaaaaaaaccccaacccchhhggmmmggggffffffffffeaaaaacccc
+abccaacccaacccaaaaccaccccaaaaaaaaaaaaacccccccccccgggggggggggffffffffffaacccccccc
+abaaaaccaaaccccaaaaaaccccaaaaaacaaaaaaccccccccccccgggggggggaaaaccffccccccccccccc
+abaaaacccccccccaaaaaaccaaaaaaaaaaaaaacccccccccccccccgggaaaaaaaacccccccccccccccca
+abaaaaacccccccaaaaaaaccaaaaaaaaaaaaaacccccccccccccccccaaacccaaaaccccccccccccccaa
+abaaaaacaaaaccaaaaaaaacaaaaaaaaaaaccccccccccccccccccccaaaccccaaaccccccccccaaacaa
+abaaaaacaaaaccaaaaaaaaaaaaaaaaaaacccccccccccccccccccccccccccccccccccccccccaaaaaa
+abaaacccaaaaccccaaaccccaaaaaaaaaaacccccccccccccccccccccccccccccccccccccccccaaaaa

src/test/kotlin/me/grison/aoc/y2022/AllDaysTest.kt

@@ -22,6 +22,7 @@ class AllDaysTest {
  Answer({ Day09() }, 6026, 2273),
  Answer({ Day10() }, 12980, "BRJLFULP"),
  Answer({ Day11() }, 76728, 21553910156),
+ Answer({ Day12() }, 391, 386),
  ).map {
  val day = it.inst.invoke()
  DynamicTest.dynamicTest("Day ${day.year}/${day.dayNumber} - Part 1 - expecting ${it.part1}") {