Solve part 1 day 11

Author: michaeltroger

src/Day11.kt

@@ -1,20 +1,121 @@
 private const val DAY = 11
-
 fun main() {
-    fun part1(input: List<String>): Int {
-        return -1
+    fun part1(octopuses: Array<IntArray>): Int {
+        var flashCount = 0
+        repeat(100) {
+            // increase energy level of all by one
+            for (x in octopuses.indices) {
+                for (y in octopuses[0].indices) {
+                    octopuses[x][y]++
+                }
+            }
+            // flash all octopuses with energy > 9 plus adjacent ones
+            val flashedOctopuses: Array<BooleanArray> = Array(10)  { BooleanArray(10) }
+            for (x in octopuses.indices) {
+                for (y in octopuses[0].indices) {
+                    if (octopuses[x][y] > 9 && !flashedOctopuses[x][y]) {
+                        //octopuses[x][y]++
+                        makeOctopusFlash(octopuses, x, y, flashedOctopuses)
+                    }
+                }
+            }
+            // reset energy level
+            for (x in octopuses.indices) {
+                for (y in octopuses[0].indices) {
+                    if (octopuses[x][y] > 9) {
+                        octopuses[x][y] = 0
+                        flashCount++
+                    }
+                }
+            }
+        }
+        return flashCount
     }
 
-    fun part2(input: List<String>): Int {
+    fun part2(octopuses: Array<IntArray>): Int {
         return -1
     }
 
     // test if implementation meets criteria from the description, like:
-    val testInput = readInput(day = DAY, useTestInput = true)
+    val testInput = readInput(day = DAY, useTestInput = true).toIntArray()
     check(part1(testInput) == 1656)
     //check(part2(testInput) == 288957)
 
-    val input = readInput(day = DAY)
+    val input = readInput(day = DAY).toIntArray()
     println(part1(input))
     println(part2(input))
 }
+
+private fun makeOctopusFlash(octopuses: Array<IntArray>, x: Int, y: Int, flashedOctopuses: Array<BooleanArray>) {
+    flashedOctopuses[x][y] = true
+
+    var xIndex = x-1
+    var yIndex = y
+    if (x > 0) {
+        octopuses[xIndex][yIndex]++
+        if (octopuses[xIndex][yIndex] > 9 && !flashedOctopuses[xIndex][yIndex]) {
+            makeOctopusFlash(octopuses, xIndex, yIndex, flashedOctopuses)
+        }
+    }
+    xIndex = x+1
+    yIndex = y
+    if (x < octopuses.size - 1) {
+        octopuses[xIndex][yIndex]++
+        if (octopuses[xIndex][yIndex] > 9 && !flashedOctopuses[xIndex][yIndex]) {
+            makeOctopusFlash(octopuses, xIndex, yIndex, flashedOctopuses)
+        }
+    }
+    xIndex = x
+    yIndex = y-1
+    if (y > 0) {
+        octopuses[xIndex][yIndex]++
+        if (octopuses[xIndex][yIndex] > 9 && !flashedOctopuses[xIndex][yIndex]) {
+            makeOctopusFlash(octopuses, xIndex, yIndex, flashedOctopuses)
+        }
+    }
+    xIndex = x
+    yIndex = y+1
+    if (y < octopuses[0].size - 1) {
+        octopuses[xIndex][yIndex]++
+        if (octopuses[xIndex][yIndex] > 9 && !flashedOctopuses[xIndex][yIndex]) {
+            makeOctopusFlash(octopuses, xIndex, yIndex, flashedOctopuses)
+        }
+    }
+
+    xIndex = x-1
+    yIndex = y-1
+    if (x > 0 && y > 0) {
+        octopuses[xIndex][yIndex]++
+        if (octopuses[xIndex][yIndex] > 9 && !flashedOctopuses[xIndex][yIndex]) {
+            makeOctopusFlash(octopuses, xIndex, yIndex, flashedOctopuses)
+        }
+    }
+    xIndex = x+1
+    yIndex = y+1
+    if (y < octopuses[0].size - 1 && x < octopuses.size - 1) {
+        octopuses[xIndex][yIndex]++
+        if (octopuses[xIndex][yIndex] > 9 && !flashedOctopuses[xIndex][yIndex]) {
+            makeOctopusFlash(octopuses, xIndex, yIndex, flashedOctopuses)
+        }
+    }
+    xIndex = x+1
+    yIndex = y-1
+    if (x < octopuses.size - 1 && y > 0) {
+        octopuses[xIndex][yIndex]++
+        if (octopuses[xIndex][yIndex] > 9 && !flashedOctopuses[xIndex][yIndex]) {
+            makeOctopusFlash(octopuses, xIndex, yIndex, flashedOctopuses)
+        }
+    }
+    xIndex = x-1
+    yIndex = y+1
+    if (y < octopuses.size - 1 && x > 0) {
+        octopuses[xIndex][yIndex]++
+        if (octopuses[xIndex][yIndex] > 9 && !flashedOctopuses[xIndex][yIndex]) {
+            makeOctopusFlash(octopuses, xIndex, yIndex, flashedOctopuses)
+        }
+    }
+}
+
+private fun List<String>.toIntArray(): Array<IntArray> {
+    return map { it.toCharArray().map { it.toString().toInt() }.toIntArray() }.toTypedArray()
+}