Day07 + optimizations

days/src/main/kotlin/Day07.kt

@@ -0,0 +1,57 @@
+package be.vandewalleh.aoc.days
+
+import be.vandewalleh.aoc.utils.input.Day
+import be.vandewalleh.aoc.utils.input.Input
+import be.vandewalleh.aoc.utils.input.Lines
+import be.vandewalleh.aoc.utils.input.createDay
+import org.eclipse.collections.api.factory.Stacks
+import org.eclipse.collections.api.multimap.list.ImmutableListMultimap
+import org.eclipse.collections.api.stack.MutableStack
+import org.eclipse.collections.impl.factory.Multimaps
+
+data class Bag(val count: Int, val color: String)
+
+@Day(7)
+class Day07(@Lines val input: Input<List<String>>) {
+
+    private val map: ImmutableListMultimap<String, Bag>
+
+    init {
+        val mutableMap = Multimaps.mutable.list.empty<String, Bag>()
+
+        val colorRegex = "^(\\w+ \\w+)".toRegex()
+        val requirementRegex = "(\\d+) (\\w+ \\w+) bag".toRegex()
+
+        for (line in input.value) {
+            val outerColor = colorRegex.find(line)!!.groupValues[1]
+            for (match in requirementRegex.findAll(line)) {
+                val (_, count, color) = match.groupValues
+                mutableMap.put(outerColor, Bag(count.toInt(), color))
+            }
+        }
+
+        map = mutableMap.toImmutable()
+    }
+
+    private fun bagSequence(rootColor: String): Sequence<Bag> = sequence {
+        val stack: MutableStack<Bag> = Stacks.mutable.ofAll(map.get(rootColor))
+        while (stack.notEmpty()) {
+            val current = stack.pop().also { yield(it) }
+            map[current.color]?.let {
+                it.forEach { (count, color) ->
+                    stack.push(Bag(current.count * count, color))
+                }
+            }
+        }
+    }
+
+    fun part1() = map.keySet().count { bagSequence(it).any { it.color == "shiny gold" } }
+
+    fun part2() = bagSequence("shiny gold").sumBy { it.count }
+
+}
+
+fun main() = with(createDay<Day07>()) {
+    println(part1())
+    println(part2())
+}