2024: day 14 part 2

src/main/kotlin/io/plagov/advent/aoc2024/Day14.kt

@@ -1,5 +1,6 @@
 package io.plagov.advent.aoc2024
 
+import java.io.File
 import kotlin.math.abs
 
 class Day14 {
@@ -27,6 +28,36 @@ class Day14 {
     return topLeft * bottomLeft * topRight * bottomRight
   }
 
+  fun partTwo(input: List<String>): Int {
+    val robots = input.map { parseInput(it) }
+    var seconds = 0
+
+    while (true) {
+      seconds++
+      for (robot in robots) {
+        move(robot)
+      }
+      val array = populateArray(robots)
+      if (hasChristmasTree(array)) {
+        break
+      }
+    }
+
+    return seconds
+  }
+
+  private fun hasChristmasTree(array: Array<CharArray>): Boolean {
+    return array.any { it.joinToString(",").contains("#,#,#,#,#,#,#,#,#,#") }
+  }
+
+  private fun populateArray(robots: List<Robot>): Array<CharArray> {
+    val array = Array(rowCount) { CharArray(colCount) { '.' } }
+    robots.forEach { robot ->
+      array[robot.pRow][robot.pCol] = '#'
+    }
+    return array
+  }
+
   private fun move(robot: Robot) {
     val rowMove = robot.pRow + robot.vRow
     val colMove = robot.pCol + robot.vCol

src/test/kotlin/io/plagov/advent/aoc2024/Day14Test.kt

@@ -14,4 +14,9 @@ class Day14Test {
   fun partOne() {
     Assertions.assertEquals(216027840, day14.partOne(input))
   }
+
+  @Test
+  fun partTwo() {
+    Assertions.assertEquals(6876, day14.partTwo(input))
+  }
 }