aoc-2024 - Day06 - part 1

Author: Krystian Kaniowski

advent-of-code-2024/src/Day06.kt

@@ -0,0 +1,104 @@
+enum class Direction(val x: Int, val y: Int) {
+ UP(0, -1),
+ RIGHT(1, 0),
+ DOWN(0, 1),
+ LEFT(-1, 0);
+
+ fun rotate() = entries[(ordinal + 1) % entries.size]
+}
+
+sealed class Field {
+ data object Guard : Field()
+ data object Wall : Field()
+ data object NotVisited : Field()
+ data object Visited : Field()
+ data object NotExists : Field()
+}
+
+data class Array2d(val xSize: Int, val ySize: Int) {
+
+ val array = Array(ySize) { Array<Field>(xSize) { Field.NotVisited } }
+
+ operator fun get(x: Int, y: Int) = if (isInBounds(x, y)) array[y][x] else Field.NotExists
+ operator fun set(x: Int, y: Int, field: Field) {
+ array[y][x] = field
+ }
+
+ fun isInBounds(x: Int, y: Int) = x in 0 until xSize && y in 0 until ySize
+
+ fun count(field: Field) = array.sumOf { it.count { it == field } }
+
+ fun printArray() {
+ for (x in array.indices) {
+ for (y in array[x].indices) {
+ print(
+ when (array[x][y]) {
+ Field.Guard -> '^'
+ Field.Wall -> '#'
+ Field.NotVisited -> '.'
+ Field.Visited -> 'X'
+ else -> ' '
+ }
+ )
+ }
+ println("")
+ }
+ println("")
+ }
+}
+
+data class Point(val x: Int, val y: Int)
+
+fun main() {
+
+ fun part1(input: List<String>): Int {
+
+ val array = Array2d(input[0].length, input.size)
+ var guardPos = Point(0, 0)
+ var direction = Direction.UP
+
+ input.forEachIndexed { y, list ->
+ list.forEachIndexed { x, char ->
+ array.set(
+ x = x,
+ y = y,
+ field = when (char) {
+ '#' -> Field.Wall
+ '.' -> Field.NotVisited
+ '^' -> {
+ guardPos = Point(x, y)
+ Field.Visited
+ }
+
+ else -> error("Unknown char: $char")
+ }
+ )
+ }
+ }
+
+ do {
+ // array.printArray()
+ while (array[guardPos.x + direction.x, guardPos.y + direction.y] == Field.Wall) {
+ direction = direction.rotate()
+ }
+ array[guardPos.x, guardPos.y] = Field.Visited
+ guardPos = Point(guardPos.x + direction.x, guardPos.y + direction.y)
+
+
+ } while (array[guardPos.x, guardPos.y] != Field.NotExists)
+
+ return array.count(Field.Visited)
+ }
+
+ fun part2(input: List<String>): Int {
+ return TODO()
+ }
+
+ val testInput = readInput("Day06_test")
+ val input = readInput("Day06")
+
+ test(41) { part1(testInput) }
+ exec { part1(input) }
+ test(TODO()) { part2(testInput) }
+ exec { part2(input) }
+}