Solved day 18 part 2

Author: Gentleman1983

build.gradle

@@ -4,7 +4,7 @@ plugins {
 
 // project meta data
 group 'de.havox_design.aoc2015'
-version '0.17.3'
+version '0.17.4'
 
 // Switch to gradle "all" distribution.
 wrapper {

day18/src/main/kotlin/de/havox_design/aoc2015/day18/GIFMatrix.kt

@@ -9,7 +9,9 @@ class GIFMatrix(private var filename: String) {
             .lights()
 
     fun processPart2(steps: Int=100): Int =
-        0
+        (1..steps)
+            .fold(data) { current, _ -> current.turnCornersOn().next().turnCornersOn() }
+            .lights()
 
     private fun readData(): BooleanGrid =
         BooleanGrid.from(getResourceAsText(filename))

day18/src/test/kotlin/de/havox_design/aoc2015/day18/Day18Test.kt

@@ -17,14 +17,29 @@ class Day18Test {
     fun testProcessPart1(filename: String, expectedResult: Int, steps: Int) =
         GIFMatrix(filename).processPart1(steps).shouldBe(expectedResult)
 
+    @ParameterizedTest
+    @MethodSource("getDataForTestProcessPart2")
+    fun testProcessPart2(filename: String, expectedResult: Int, steps: Int) =
+        GIFMatrix(filename).processPart2(steps).shouldBe(expectedResult)
+
     companion object {
         @JvmStatic
         private fun getDataForTestProcessPart1(): Stream<Arguments> =
             Stream.of(
-                Arguments.of("part1sample.txt", 11, 1),
-                Arguments.of("part1sample.txt", 8, 2),
-                Arguments.of("part1sample.txt", 4, 3),
-                Arguments.of("part1sample.txt", 4, 4)
+                Arguments.of("sample.txt", 11, 1),
+                Arguments.of("sample.txt", 8, 2),
+                Arguments.of("sample.txt", 4, 3),
+                Arguments.of("sample.txt", 4, 4)
+            )
+
+        @JvmStatic
+        private fun getDataForTestProcessPart2(): Stream<Arguments> =
+            Stream.of(
+                Arguments.of("sample.txt", 18, 1),
+                Arguments.of("sample.txt", 18, 2),
+                Arguments.of("sample.txt", 18, 3),
+                Arguments.of("sample.txt", 14, 4),
+                Arguments.of("sample.txt", 17, 5)
             )
     }
 }