Optimize part2 + benchmark

days/src/main/kotlin/Day16.kt

@@ -4,8 +4,9 @@ import be.vandewalleh.aoc.utils.input.Day
 import be.vandewalleh.aoc.utils.input.Groups
 import be.vandewalleh.aoc.utils.input.Input
 import be.vandewalleh.aoc.utils.input.createDay
+import org.eclipse.collections.api.multimap.list.MutableListMultimap
+import org.eclipse.collections.api.multimap.set.MutableSetMultimap
 import org.eclipse.collections.impl.factory.Multimaps
-import org.eclipse.collections.impl.factory.primitive.IntSets
 
 @Day(16)
 class Day16(@Groups val input: Input<List<List<String>>>) {
@@ -42,7 +43,7 @@ class Day16(@Groups val input: Input<List<List<String>>>) {
         return invalid.sum()
     }
 
-    private fun isTicketValid(ticket: List<Int>, ranges: List<IntRange>): Boolean {
+    private fun isTicketValid(ticket: List<Int>, ranges: Iterable<IntRange>): Boolean {
         for (number in ticket) {
             if (!ranges.any { number in it }) return false
         }
@@ -52,26 +53,59 @@ class Day16(@Groups val input: Input<List<List<String>>>) {
     private fun inRanges(value: Int, ranges: List<IntRange>) = ranges.any { value in it }
 
     fun part2(): Long {
-        val minMax = Multimaps.mutable.list.empty<String, IntRange>()
+        val rangesByName = namedRanges()
+        val validTickets = validTickets(rangesByName)
+        val indexesByCategory = indexesByCategory(rangesByName, validTickets)
 
-        for (line in rangesGroup) {
-            val name = line.substringBefore(":")
-            extractRanges(line).forEach {
-                minMax.put(name, it)
+        removeDuplicates(indexesByCategory)
+
+        val myTicketValues = myTicket.split(",").map { it.toInt() }
+
+        var mult = 1L
+        indexesByCategory.forEachKeyValue { category, index ->
+            if (category.startsWith("departure")) {
+                mult *= myTicketValues[index]
             }
         }
 
-        val validTickets = mutableListOf<List<Int>>()
-        for (line in nearbyTicketsGroup) {
-            val ticket = line.splitToSequence(",").map { it.toInt() }.toList()
-            if (isTicketValid(ticket, minMax.valuesView().toList())) {
-                validTickets.add(ticket)
+        return mult
+    }
+
+    private fun removeDuplicates(indexesByCategory: MutableSetMultimap<String, Int>) {
+        val toBeRemoved = HashSet<Int>()
+        val queue = ArrayDeque<Int>()
+
+        indexesByCategory.multiValuesView()
+            .sortedBy { it.size() }
+            .forEach { it.forEach { if (toBeRemoved.add(it)) queue.add(it) } }
+
+        queue.removeLast()
+
+        val categoriesToRemove = mutableListOf<String>()
+
+        while (queue.isNotEmpty()) {
+            val duplicate = queue.removeFirst()
+
+            categoriesToRemove.clear()
+
+            for (entry in indexesByCategory.keyMultiValuePairsView()) {
+                if (entry.two.size() < 2) continue
+                categoriesToRemove.add(entry.one)
+            }
+
+            for (category in categoriesToRemove) {
+                indexesByCategory.remove(category, duplicate)
             }
         }
+    }
 
-        val indexesByCategory = Multimaps.mutable.list.empty<String, Int>()
+    private fun indexesByCategory(
+        rangesByName: MutableListMultimap<String, IntRange>,
+        validTickets: MutableList<List<Int>>,
+    ): MutableSetMultimap<String, Int> {
+        val indexesByCategory = Multimaps.mutable.set.empty<String, Int>()
 
-        for (entry in minMax.keyMultiValuePairsView()) {
+        for (entry in rangesByName.keyMultiValuePairsView()) {
             val category = entry.one
             val ranges = entry.two.toList()
 
@@ -83,38 +117,29 @@ class Day16(@Groups val input: Input<List<List<String>>>) {
                 if (allInRange) indexesByCategory.put(category, i)
             }
         }
+        return indexesByCategory
+    }
 
-        val removed = IntSets.mutable.empty()
-        while (!indexesByCategory.multiValuesView().all { it.size() == 1 }) {
-            val values = indexesByCategory.multiValuesView()
-            val categoriesToRemove = mutableListOf<String>()
-
-            val one = values.filter { it.size() == 1 }
-                .map { it.first() }
-                .find { removed.add(it) }
-                ?: error("No values left to remove")
-
-            for (entry in indexesByCategory.keyMultiValuePairsView()) {
-                val values = entry.two
-                if (values.size() < 2) continue
-                val category = entry.one
-                if (values.find { it == one } != null) categoriesToRemove.add(category)
-            }
-
-            for (category in categoriesToRemove) {
-                indexesByCategory.remove(category, one)
+    private fun validTickets(rangesByName: MutableListMultimap<String, IntRange>): MutableList<List<Int>> {
+        val validTickets = mutableListOf<List<Int>>()
+        for (line in nearbyTicketsGroup) {
+            val ticket = line.splitToSequence(",").map { it.toInt() }.toList()
+            if (isTicketValid(ticket, rangesByName.valuesView().toList())) {
+                validTickets.add(ticket)
             }
         }
-        val myTicketValues = myTicket.split(",").map { it.toInt() }
-        var mult = 1L
+        return validTickets
+    }
 
-        indexesByCategory.forEachKeyValue { category, index ->
-            if (category.startsWith("departure")) {
-                mult *= myTicketValues[index]
+    private fun namedRanges(): MutableListMultimap<String, IntRange> {
+        val rangesByName = Multimaps.mutable.list.empty<String, IntRange>()
+        for (line in rangesGroup) {
+            val name = line.substringBefore(":")
+            extractRanges(line).forEach {
+                rangesByName.put(name, it)
             }
         }
-
-        return mult
+        return rangesByName
     }
 }