diff --git a/days/src/main/kotlin/Day14.kt b/days/src/main/kotlin/Day14.kt
index b30184a..517d74f 100644
--- a/days/src/main/kotlin/Day14.kt
+++ b/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.ObjectLongMaps
+import org.eclipse.collections.impl.factory.primitive.ObjectIntMaps
 
 @Day(14)
 class Day14(@Lines val input: Input<List<String>>) {
@@ -42,48 +42,23 @@ class Day14(@Lines val input: Input<List<String>>) {
     }
 
     fun part2(): Long {
-        val mem = ObjectLongMaps.mutable.empty<String>()
+        val mem = ObjectIntMaps.mutable.empty<String>()
 
-        var currentMask: String = ""
+        var currentMask = ""
 
         for (line in input.value) {
-            if (line.startsWith("mask")) {
-                currentMask = line.removePrefix("mask = ")
+            if (line[1] == 'a') {
+                currentMask = line.substring(7)
             } else {
+
                 val (address, value) = memRe.find(line)!!.destructured.let { (add, value) ->
-                    add.toLong().toBin36() to value.toLong()
+                    add.toLong().toBin36() to value.toInt()
                 }
 
-                val addresses = address.zip(currentMask).map { (address, mask) ->
-                    when (mask) {
-                        'X' -> arrayOf('0', '1')
-                        '1' -> arrayOf('1')
-                        else -> arrayOf(address)
-                    }
-                }
+                val builders = generateMutations(currentMask, address)
 
-                val mutations = currentMask.count { it == 'X' }.let { 2.0.pow(it.toDouble()).toInt() }
-                val builders = Array(mutations) { StringBuilder() }
-
-                var groups = 1
-
-                for (address in addresses) {
-                    if (address.size > 1) {
-                        groups *= 2
-                        val groupSize = mutations / groups
-                        var j = 0
-                        for (i in 0 until mutations) {
-                            val flip = i % groupSize == 0
-                            if (flip) j = if (j == 0) 1 else 0
-                            builders[i].append(address[j])
-                        }
-                    } else {
-                        builders.forEach { it.append(address[0]) }
-                    }
-                }
-
-                builders.map { it.toString() }.forEach { address ->
-                    mem.put(address, value)
+                for (builder in builders) {
+                    mem.put(builder.toString(), value)
                 }
             }
         }
@@ -91,6 +66,36 @@ 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) }
+
+        var groups = 1
+
+        for (i in mask.indices) {
+            when (mask[i]) {
+                'X' -> {
+                    groups *= 2
+                    val groupSize = mutations / groups
+                    var j = 1
+                    for (b in builders.indices) {
+                        val builder = builders[b]
+                        val flip = b % groupSize == 0
+                        if (flip) j = if (j == 0) 1 else 0
+                        builder.append(j)
+                    }
+                }
+                '1' -> {
+                    builders.forEach { it.append('1') }
+                }
+                else -> {
+                    builders.forEach { it.append(address[i]) }
+                }
+            }
+        }
+        return builders
+    }
+
 }
 
 fun main() = with(createDay<Day14>()) {