2024 - Day 14 - part 1

src/main/kotlin/no/rodland/advent_2024/Day14.kt

@@ -2,32 +2,59 @@ package no.rodland.advent_2024
 
 import no.rodland.advent.Day
 import no.rodland.advent.Pos
+import product
 
 // template generated: 14/12/2024
 // Fredrik Rødland 2024
 
-class Day14(val input: List<String>) : Day<Long, Long, List<Day14.Robot>> {
+class Day14(val input: List<String>, val width: Int, val height: Int) : Day<Long, Long, List<Day14.Robot>> {
 
     private val robots = input.parse()
 
     override fun partOne(): Long {
-        return 2
+        return robots.map { it.move(100, width, height) }
+            .groupBy { it.quadrant(width, height) }
+            .toSortedMap()
+            .filterKeys { i: Int -> i != 0 } // middle
+            .values
+            .map { it.size }
+            .product()
     }
 
     override fun partTwo(): Long {
         return 2
     }
 
+    data class Robot(val pos: Pos, val vel: Pos) {
+        fun move(iterations: Int, width: Int, height: Int): Pos {
+            val x = (pos.x + (((iterations) * vel.x) % width) + width) % width
+            val y = (pos.y + (((iterations) * vel.y) % height) + height) % height
+            return Pos(x, y)
+        }
+    }
+
+    private fun Pos.quadrant(width: Int, height: Int): Int {
+        val firstX = this.x < (width / 2)
+        val lastX = this.x >= ((width / 2) + 1)
+        val firstY = this.y < (height / 2)
+        val lastY = this.y >= ((height / 2) + 1)
+        return when {
+            firstX && firstY -> 1
+            lastX && firstY -> 2
+            firstX && lastY -> 3
+            lastX && lastY -> 4
+            else -> 0
+        }
+    }
+
     override fun List<String>.parse(): List<Robot> {
         return map { line ->
-            // p=0,4 v=3,-3
             val (px, py) = line.substringAfter("p=").substringBefore(" v=").split(",").map { it.toInt() }
             val (vx, vy) = line.substringAfter("v=").split(",").map { it.toInt() }
             Robot(Pos(px, py), Pos(vx, vy))
         }
     }
 
-    data class Robot(val pos: Pos, val vel: Pos)
-
     override val day = "14".toInt()
 }
+

src/test/kotlin/no/rodland/advent_2024/Day14Test.kt

@@ -15,20 +15,24 @@ internal class Day14Test {
     private val data14 = "2024/input_14.txt".readFile()
     private val test14 = "2024/input_14_test.txt".readFile()
 
-    private val resultTestOne = 2L
+    private val resultTestOne = 12L
     private val resultTestTwo = 2L
-    private val resultOne = 2L
+    private val resultOne = 221142636L
     private val resultTwo = 2L
+//    private val width = 101
+//    private val height = 103
+//    private val widthExample = 11
+//    private val heightExample = 7
 
     val test = defaultTestSuiteParseOnInit(
-        Day14(data14),
-        Day14(test14),
+        Day14(data14, 101, 103),
+        Day14(test14, 11, 7),
         resultTestOne,
         resultOne,
         resultTestTwo,
         resultTwo,
-        { Day14(data14) },
-        { Day14(test14) },
+        { Day14(data14, 101, 103) },
+        { Day14(test14, 11, 7) },
     )
 
     @Nested