Optimize Day14 + benchmarks

days/src/main/kotlin/Day14.kt

@@ -6,7 +6,7 @@ import be.vandewalleh.aoc.utils.input.Lines
 import be.vandewalleh.aoc.utils.input.createDay
 import kotlin.math.pow
 import org.eclipse.collections.impl.factory.primitive.IntObjectMaps
-import org.eclipse.collections.impl.factory.primitive.ObjectIntMaps
+import org.eclipse.collections.impl.factory.primitive.LongIntMaps
 
 @Day(14)
 class Day14(@Lines val input: Input<List<String>>) {
@@ -42,7 +42,7 @@ class Day14(@Lines val input: Input<List<String>>) {
     }
 
     fun part2(): Long {
-        val mem = ObjectIntMaps.mutable.empty<String>()
+        val mem = LongIntMaps.mutable.empty()
 
         var currentMask = ""
 
@@ -55,10 +55,10 @@ class Day14(@Lines val input: Input<List<String>>) {
                     add.toLong().toBin36() to value.toInt()
                 }
 
-                val builders = generateMutations(currentMask, address)
+                val mutations = generateMutations(currentMask, address)
 
-                for (builder in builders) {
-                    mem.put(builder.toString(), value)
+                for (mutation in mutations) {
+                    mem.put(String(mutation).toLong(2), value)
                 }
             }
         }
@@ -66,9 +66,9 @@ class Day14(@Lines val input: Input<List<String>>) {
         return mem.values().sum()
     }
 
-    private fun generateMutations(mask: String, address: String): Array<StringBuilder> {
-        val mutations = mask.count { it == 'X' }.let { 2.0.pow(it.toDouble()).toInt() }
-        val builders = Array(mutations) { StringBuilder(36) }
+    private fun generateMutations(mask: String, address: String): Array<CharArray> {
+        val mutationCount = mask.count { it == 'X' }.let { 2.0.pow(it.toDouble()).toInt() }
+        val mutations = Array(mutationCount) { CharArray(36) }
 
         var groups = 1
 
@@ -76,24 +76,20 @@ class Day14(@Lines val input: Input<List<String>>) {
             when (mask[i]) {
                 'X' -> {
                     groups *= 2
-                    val groupSize = mutations / groups
-                    var j = 1
-                    for (b in builders.indices) {
-                        val builder = builders[b]
+                    val groupSize = mutationCount / groups
+                    var currentChar = '1'
+                    for (b in mutations.indices) {
+                        val builder = mutations[b]
                         val flip = b % groupSize == 0
-                        if (flip) j = if (j == 0) 1 else 0
-                        builder.append(j)
+                        if (flip) currentChar = if (currentChar == '0') '1' else '0'
+                        builder[i] = currentChar
                     }
                 }
-                '1' -> {
-                    builders.forEach { it.append('1') }
-                }
-                else -> {
-                    builders.forEach { it.append(address[i]) }
-                }
+                '1' -> mutations.forEach { it[i] = '1' }
+                else -> mutations.forEach { it[i] = address[i] }
             }
         }
-        return builders
+        return mutations
     }
 
 }