Day 14 Part 1

2024/src/main/kotlin/day14.kt

@@ -0,0 +1,51 @@
+fun main() {
+    val initial = "p=(-?\\d+),(-?\\d+) v=(-?\\d+),(-?\\d+)".toRegex().findAll(readInputString("day14.txt"))
+        .map {
+            Robot(
+                Grid.Coordinate(it.groupValues[1].toInt(), it.groupValues[2].toInt()),
+                Grid.Coordinate(it.groupValues[3].toInt(), it.groupValues[4].toInt())
+            )
+        }
+        .toList()
+
+    val robots = initial
+        .map { it.move(100) }
+        .toList()
+
+    var topLeft = 0
+    var topRight = 0
+    var bottomLeft = 0
+    var bottomRight = 0
+
+
+    for (robot in robots) {
+        require(robot.position.x in 0..<WIDTH)
+        require(robot.position.y in 0..<HEIGHT)
+
+        val isTop = robot.position.y < HEIGHT / 2
+        val isBottom = robot.position.y > HEIGHT / 2
+        val isLeft = robot.position.x < WIDTH / 2
+        val isRight = robot.position.x > WIDTH / 2
+
+        when {
+            isTop && isLeft -> ++topLeft
+            isTop && isRight -> ++topRight
+            isBottom && isLeft -> ++bottomLeft
+            isBottom && isRight -> ++bottomRight
+        }
+    }
+    val part1 = topLeft * topRight * bottomLeft * bottomRight
+    println("Part 1: $part1")
+}
+
+private const val WIDTH = 101
+
+private const val HEIGHT = 103
+
+data class Robot(val position: Grid.Coordinate, val velocity: Grid.Coordinate) {
+    fun move(t: Int): Robot {
+        val newX = (t * WIDTH + position.x + t * velocity.x) % WIDTH
+        val newY = (t * HEIGHT + position.y + t * velocity.y) % HEIGHT
+        return copy(position = Grid.Coordinate(newX, newY))
+    }
+}