AOC - Day 16

Author: cortinico

src/main/java/Exercise16-part2.kt

@@ -0,0 +1,61 @@
+fun main() {
+ val input = object {}.javaClass.getResource("input-16.txt").readText().split("\n\n")
+
+ val ranges = input[0].split("\n")
+ .associateBy({
+ it.substring(0, it.indexOf(":"))
+ }, {
+ it.substring(it.indexOf(":") + 1)
+ .replace(" or", "")
+ .trim()
+ .split(" ")
+ .map { range ->
+ range.split("-").let { it[0].toInt()..it[1].toInt() }
+ }
+ })
+
+ val myTicket = input[1].split("\n")[1]
+ .split(",")
+ .map(String::toLong)
+
+ val validTickets = input[2].split("\n")
+ .drop(1)
+ .map { it.split(",").map(String::toInt) }
+ .filter {
+ it.all { value ->
+ ranges.any { entry ->
+ entry.value.any { range -> value in range }
+ }
+ }
+ }
+
+ val possibleRules = (myTicket.indices).map { index ->
+ ranges.values
+ .mapIndexed { rangeIndex, ranges ->
+ rangeIndex to ranges
+ }
+ .filter { (_, ranges) ->
+ validTickets.all { ticket -> ranges.any { range -> ticket[index] in range } }
+ }
+ .map { (rangeIndex, _) -> rangeIndex }
+ .toMutableList()
+ }.toMutableList()
+
+ val ordering = IntArray(possibleRules.size)
+
+ while (possibleRules.any { it.isNotEmpty() }) {
+ val indexToRemove = possibleRules.indexOfFirst { it.size == 1 }
+ val valueToRemove = possibleRules[indexToRemove][0]
+ possibleRules[indexToRemove].clear()
+ ordering[indexToRemove] = valueToRemove
+ possibleRules.onEach { it.remove(valueToRemove) }
+ }
+
+ ranges.entries
+ .asSequence()
+ .filter { it.key.startsWith("departure") }
+ .mapIndexed { index, entry -> index to entry.key }
+ .map { (index, _) -> myTicket[ordering.indexOf(index)] }
+ .fold(1L) { acc, next -> acc * next }
+ .also(::println)
+}

src/main/java/Exercise16.kt

@@ -0,0 +1,26 @@
+fun main() {
+ val input = object {}.javaClass.getResource("input-16.txt").readText().split("\n\n")
+
+ val ranges = input[0].split("\n")
+ .flatMap { line ->
+ line.substring(line.indexOf(":") + 1)
+ .replace(" or", "")
+ .trim()
+ .split(" ")
+ .map { range ->
+ range.split("-").let { bounds ->
+ bounds[0].toInt()..bounds[1].toInt()
+ }
+ }
+ }
+
+ input[2].split("\n")
+ .drop(1)
+ .flatMap {
+ it.split(",")
+ }
+ .map { it.toInt() }
+ .filter { value -> ranges.all { range -> value !in range } }
+ .sum()
+ .also(::println)
+}