Day 10!

day10.kts

@@ -0,0 +1,82 @@
+#!/usr/bin/env kotlin
+import java.util.Scanner
+
+
+    class TrailHead(var x: Int, var y: Int, private val map: Map) {
+        private val peaks = mutableMapOf<Pair<Int, Int>, Int>()
+        fun getScore(): Int {
+            if (this.peaks.isEmpty()) {
+                for (peak in this.walkToPeak(this.x, this.y)) {
+                    this.peaks[peak] = (this.peaks[peak] ?: 0) + 1
+                }
+            }
+            return this.peaks.keys.size
+        }
+        fun getGetRating(): Int {
+            this.getScore()
+            return this.peaks.values.sum()
+        }
+
+        private fun walkToPeak(x: Int, y: Int, previous: Int = -1): List<Pair<Int, Int>> {
+            if (x < 0 || x >= map.getLength() || y < 0 || y >= map.getHeight() || map.get(x, y) != (previous + 1)) {
+                return listOf()
+            } else if (map.get(x, y) == 9) {
+                return listOf(Pair(x, y))
+            } else {
+                val current = map.get(x, y)
+                return walkToPeak(x + 1, y, current) + walkToPeak(x - 1, y, current) + walkToPeak(x, y + 1, current) + walkToPeak(x, y - 1, current)
+            }
+        }
+
+    }
+
+    class Map(private val grid: List<List<Int>>) {
+        private val trailHeads = mutableListOf<TrailHead>()
+
+        init {
+            grid.forEachIndexed { y, row ->
+                row.forEachIndexed { x, height ->
+                    if (height == 0) {
+                        trailHeads.add(TrailHead(x, y, this))
+                    }
+                }
+            }
+        }
+
+        fun addTrailHead(trailHead: TrailHead) {
+            trailHeads.add(trailHead)
+        }
+
+        fun get(x: Int, y: Int): Int {
+            return grid[y][x]
+        }
+
+        fun getHeight(): Int {
+            return grid.size
+        }
+
+        fun getLength(): Int {
+            return if (grid.isNotEmpty()) grid[0].size else 0
+        }
+
+        fun getScore(): Int {
+            return trailHeads.fold(0) { acc, trailHead -> acc + trailHead.getScore() }
+        }
+
+        fun getGetRating(): Int {
+            return trailHeads.fold(0) { acc, trailHead -> acc + trailHead.getGetRating() }
+        }
+    }
+
+
+val scanner = Scanner(System.`in`)
+val mapInput = mutableListOf<List<Int>>()
+while (scanner.hasNext()) {
+    val line = scanner.nextLine()
+    val numbers = line.split("").filter { it.isNotEmpty() }.map { it.toInt() }
+    mapInput.add(numbers)
+}
+val map = Map(mapInput.reversed())
+
+println("Score: ${map.getScore()}")
+println("Rating: ${map.getGetRating()}")

day10.kts.testvalue

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+Score: 754
+Rating: 1609