day06

app/src/main/kotlin/day06/Day06.kt

@@ -0,0 +1,107 @@
+package day06
+
+import kotlin.io.println
+import kotlin.collections.listOf
+
+class Day06 {
+    fun parse(input: String): MutableList<MutableList<Tile>> {
+        return input.lines().map {line -> line.map {Tile.fromChar(it)}.toMutableList() }.toMutableList()
+    }
+
+    fun part1(input: String): Int {
+        var map = parse(input)
+        var running = true
+        var pos = Pair(59, 62)
+        var dir: Direction = Direction.Up
+        var count = 1
+        while (running) {
+            val newX = pos.first + dir.delta.first
+            val newY = pos.second + dir.delta.second
+            if (map[pos.first][pos.second] == Tile.Empty) {
+                map[pos.first][pos.second] = Tile.Visited
+                count += 1
+            }
+            if (newX >= map.count() || newX < 0 || newY >= map[0].count() || newY < 0) {
+                return count
+            }
+            if (map[newX][newY] == Tile.Wall) {
+                dir = Direction.rotate(dir)
+                continue
+            }
+            pos = Pair(newX, newY)
+        }
+        throw NotImplementedError()
+    }
+
+    fun runGuard(map: List<List<Tile>>): Boolean {
+        var running = true
+        //var pos = Pair(59, 62)
+        var pos = Pair(6, 4)
+        var dir: Direction = Direction.Up
+        while (running) {
+            val newX = pos.first + dir.delta.first
+            val newY = pos.second + dir.delta.second
+            if (newX >= map.count() || newX < 0 || newY >= map[0].count() || newY < 0) {
+                return false
+            }
+            if (map[newX][newY] == Tile.Start && dir == Direction.Up) {
+                println("$newX, $newY")
+                return true
+            }
+
+            if (map[newX][newY] == Tile.Wall) {
+                dir = Direction.rotate(dir)
+                continue
+            }
+            pos = Pair(newX, newY)
+        }
+        throw NotImplementedError()
+    }
+
+    fun part2(input: String): Int {
+        val map = parse(input)
+        var count = 0
+        for (i in 0..<map.count()) {
+            for (j in 0..<map[0].count()) {
+                var modMap = map.map { it.toMutableList() }.toMutableList()
+                modMap[i][j] = Tile.Wall
+                if (runGuard(map)) {
+                    count += 1
+                }
+            }
+        }
+        return count
+    }
+}
+
+enum class Direction(val delta: Pair<Int, Int>) {
+    Up(Pair(-1, 0)), Down(Pair(1, 0)), Left(Pair(0,-1)), Right(Pair(0,1));
+
+    companion object {
+        fun rotate(tile: Direction): Direction {
+            return when (tile) {
+                Up -> Right
+                Right -> Down
+                Down -> Left
+                Left -> Up
+            }
+        }
+    }
+}
+
+enum class Tile {
+    Wall, Visited, Empty, Start;
+
+    companion object {
+        fun fromChar(char: Char): Tile {
+            return when (char) {
+                '.' -> Empty
+                '#' -> Wall
+                '^' -> Start
+                else -> {
+                    throw IllegalArgumentException()
+                }
+            }
+        }
+    }
+}

app/src/test/kotlin/day06/Day06Test.kt

@@ -0,0 +1,42 @@
+package day06
+
+import kotlin.test.Test
+import util.InputDownloader
+
+class Day06Test {
+    val dayNum = 6
+    val day = Day06()
+
+    val input = InputDownloader().getInput(dayNum)
+    val example = InputDownloader().getExample(dayNum)
+
+    //@Test fun part1Example() {
+    //    part1(example, 41)
+    //}
+
+    @Test fun part1Solution() {
+        part1(input, 6041)
+    }
+
+    @Test fun part2Example() {
+        part2(example, 123)
+    }
+/*
+    @Test fun part2Solution() {
+        part2(input, 4884)
+    }
+*/
+
+    fun part1(input: String, expected: Int) {
+        val output = day.part1(input)
+        println("output: $output")
+        assert(output == expected)
+    }
+
+    fun part2(input: String, expected: Int) {
+        val output = day.part2(input)
+        println("output: $output")
+        assert(output == expected)
+    }
+}
+