Solved day12 part 2

Author: Gentleman1983

build.gradle

@@ -4,7 +4,7 @@ plugins {
 
 // project meta data
 group 'de.havox_design.aoc2023'
-version '0.11.4'
+version '0.11.5'
 
 // Switch to gradle "all" distribution.
 wrapper {

day12/src/main/kotlin/de/havox_design/aoc2023/day12/Day12.kt

@@ -3,6 +3,14 @@ package de.havox_design.aoc2023.day12
 class Day12(private var filename: String) {
     private val DATA_DELIMITER = " "
     private val GROUPS_DELIMITER = ","
+    private val ICON_BROKEN_SPRING = "#"
+    private val ICON_OPERATIONAL_SPRING = "."
+    private val ICON_UNKNOWN_SPRING = '?'
+
+    // For Quicksolve
+    private var springs: String = ""
+    private var sizes: ArrayList<Int> = ArrayList<Int>()
+    private val cache = HashMap<Pair<Int, Int>, Long>()
 
     fun solvePart1(): Long =
         getResourceAsText(filename)
@@ -22,6 +30,76 @@ class Day12(private var filename: String) {
                     .count()
             }
 
+    fun quicksolvePart2(): Long {
+        var sum = 0L
+
+        for (row in getResourceAsText(filename)) {
+            springs = row
+                .split(DATA_DELIMITER)[0]
+            val tmpSizes = ArrayList(
+                row
+                    .split(DATA_DELIMITER)[1]
+                    .split(GROUPS_DELIMITER)
+                    .map { it.toInt() }
+                    .toList()
+            )
+            cache.clear()
+
+            springs = "$springs?$springs?$springs?$springs?$springs"
+            sizes.clear();
+            for (i in 1..5) {
+                sizes.addAll(tmpSizes)
+            }
+
+            sum += matches("", 0)
+        }
+
+        return sum
+    }
+
+    private fun matched(prefix: String): Boolean =
+        prefix
+            .filterIndexed { index, c -> c == springs[index] || springs[index] == ICON_UNKNOWN_SPRING }
+            .count() == prefix.length
+
+    @SuppressWarnings("kotlin:S6611", "kotlin:S6510")
+    private fun matches(prefix: String, group: Int): Long {
+        when {
+            prefix.length > springs.length -> return 0
+            cache.contains(Pair(prefix.length, group)) -> {
+                return cache[Pair(prefix.length, group)]!!
+            }
+
+            group == sizes.size -> {
+                return when {
+                    matched(prefix + ICON_OPERATIONAL_SPRING.repeat(springs.length - prefix.length)) -> 1
+                    else -> 0
+                }
+            }
+
+            else -> {
+                var result: Long = 0
+
+                for (i in 0..<(springs.length - sizes[group])) {
+                    var p = prefix;
+
+                    when {
+                        group > 0 -> p += ICON_OPERATIONAL_SPRING
+                    }
+
+                    p += ICON_OPERATIONAL_SPRING.repeat(i) + ICON_BROKEN_SPRING.repeat(sizes[group])
+
+                    when {
+                        p.length <= springs.length && matched(p) -> result += matches(p, group + 1)
+                    }
+                }
+
+                cache[Pair(prefix.length, group)] = result
+                return result
+            }
+        }
+    }
+
     private fun parseInput(row: String, folded: Boolean = false): Record {
         val (text, groups) = row
             .split(DATA_DELIMITER)
@@ -33,7 +111,13 @@ class Day12(private var filename: String) {
             folded -> {
                 Record(
                     "$text?$text?$text?$text?$text",
-                    listOf(groupDistribution, groupDistribution, groupDistribution, groupDistribution, groupDistribution)
+                    listOf(
+                        groupDistribution,
+                        groupDistribution,
+                        groupDistribution,
+                        groupDistribution,
+                        groupDistribution
+                    )
                         .flatten()
                 )
             }

day12/src/main/kotlin/de/havox_design/aoc2023/day12/MainClass.kt

@@ -7,7 +7,7 @@ class MainClass {
             val filename = "day12.txt"
 
             println("Solution part 1: ${Day12(filename).solvePart1()}")
-            println("Solution part 2: ${Day12(filename).solvePart2()}")
+            println("Solution part 2: ${Day12(filename).quicksolvePart2()}")
         }
     }
 }

day12/src/test/kotlin/de/havox_design/aoc2023/day12/Day12Test.kt

@@ -1,6 +1,7 @@
 package de.havox_design.aoc2023.day12
 
 import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Disabled
 import org.junit.jupiter.api.Test
 import org.junit.jupiter.params.ParameterizedTest
 import org.junit.jupiter.params.provider.Arguments
@@ -18,11 +19,17 @@ class Day12Test {
     fun testSolvePart1(filename: String, expectedResult: Long) =
         Day12(filename).solvePart1().shouldBe(expectedResult)
 
+    @Disabled("takes much toooooooooooooooooo long...")
     @ParameterizedTest
     @MethodSource("getDataForTestSolvePart2")
     fun testSolvePart2(filename: String, expectedResult: Long) =
         Day12(filename).solvePart2().shouldBe(expectedResult)
 
+    @ParameterizedTest
+    @MethodSource("getDataForTestSolvePart2")
+    fun testQuicksolvePart2(filename: String, expectedResult: Long) =
+        Day12(filename).quicksolvePart2().shouldBe(expectedResult)
+
     companion object {
         @JvmStatic
         private fun getDataForTestSolvePart1(): Stream<Arguments> =