Day16

2020-12-16 09:00:18 +01:00
parent 2aa4226083
commit 90c9961d72
2 changed files with 401 additions and 0 deletions
@@ -0,0 +1,138 @@
+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.RichIterable
+import org.eclipse.collections.impl.factory.Multimaps
+import org.eclipse.collections.impl.factory.primitive.IntSets
+
+@Day(16)
+class Day16(@Lines val input: Input<List<String>>) {
+
+    fun part1(): Int {
+        val minMax = mutableListOf<IntRange>()
+
+        val re = "(\\d+)-(\\d+)".toRegex()
+        for (line in input.value) {
+            re.findAll(line).forEach {
+                val (min, max) = it.destructured
+                minMax.add(min.toInt()..max.toInt())
+            }
+            if (line.startsWith("your ticket")) break
+        }
+
+        var ok = false
+        val nearbyTickets = mutableListOf<Int>()
+        for (line in input.value) {
+            if (!ok && line.startsWith("nearby tickets:")) {
+                ok = true
+                continue
+            }
+            if (!ok) continue
+            line.splitToSequence(",").forEach { nearbyTickets.add(it.toInt()) }
+        }
+
+        val invalid = mutableListOf<Int>()
+        nearbyTickets.forEach { number ->
+            if (minMax.none { number in it }) invalid.add(number)
+        }
+
+        return invalid.sum()
+    }
+
+    private fun isTicketValid(ticket: List<Int>, ranges: List<IntRange>): Boolean {
+        for (number in ticket) {
+            if (!ranges.any { number in it }) return false
+        }
+        return true
+    }
+
+    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 re = "(\\d+)-(\\d+)".toRegex()
+        for (line in input.value) {
+            if (line.startsWith("your ticket")) break
+            val name = line.split(':')[0]
+            re.findAll(line)!!.forEach {
+                val (min, max) = it.destructured
+                minMax.put(name, min.toInt()..max.toInt())
+            }
+        }
+
+        var ok = false
+        val validTickets = mutableListOf<List<Int>>()
+
+        for (line in input.value) {
+            if (!ok && line.startsWith("nearby tickets:")) {
+                ok = true
+                continue
+            }
+            if (!ok) continue
+            val ticket = line.splitToSequence(",").map { it.toInt() }.toList()
+            if (isTicketValid(ticket, minMax.valuesView().toList())) {
+                validTickets.add(ticket)
+            }
+        }
+
+        val catMap = Multimaps.mutable.list.empty<String, Int>()
+
+        for (a in minMax.keyMultiValuePairsView()) {
+            val category = a.one
+            val ranges = a.two.toList()
+
+            for (i in validTickets.first().indices) {
+                val allInRange = validTickets
+                    .asSequence()
+                    .map { it[i] }
+                    .all { inRanges(it, ranges) }
+                if (allInRange) catMap.put(category, i)
+            }
+        }
+
+        val removed = IntSets.mutable.empty()
+        while (!catMap.multiValuesView().all { it.size() == 1 }) {
+            val values = catMap.multiValuesView()
+            val categoriesToRemove = mutableListOf<String>()
+
+            val one = values.filter { it.size() == 1 }
+                .map { it.first() }
+                .find { !removed.contains(it) }
+                ?.also { removed.add(it) }
+                ?: error("???")
+
+            for (v in catMap.keyMultiValuePairsView()) {
+                val cat = v.one
+                val values: RichIterable<Int> = v.two
+                if (values.size() < 2) continue
+                if (values.find { it == one } != null) categoriesToRemove.add(cat)
+            }
+
+            for (cat in categoriesToRemove) {
+                catMap.remove(cat, one)
+            }
+        }
+
+        // TODO
+        val myTicket = "173,191,61,199,101,179,257,79,193,223,139,97,83,197,251,53,89,149,181,59"
+
+        val myTicketValues = myTicket.split(",").map { it.toInt() }
+        var mult = 1L
+        catMap.forEachKeyValue { category, index ->
+            if (category.startsWith("departure")) {
+                mult *= myTicketValues[index]
+            }
+        }
+
+        return mult
+    }
+}
+
+fun main() = with(createDay<Day16>()) {
+    println(part1())
+    println(part2())
+}