diff --git a/input/day02 b/input/day02 new file mode 100644 index 0000000..5066627 --- /dev/null +++ b/input/day02 @@ -0,0 +1 @@ +990244-1009337,5518069-5608946,34273134-34397466,3636295061-3636388848,8613701-8663602,573252-688417,472288-533253,960590-988421,7373678538-7373794411,178-266,63577667-63679502,70-132,487-1146,666631751-666711926,5896-10827,30288-52204,21847924-21889141,69684057-69706531,97142181-97271487,538561-555085,286637-467444,93452333-93519874,69247-119122,8955190262-8955353747,883317-948391,8282803943-8282844514,214125-236989,2518-4693,586540593-586645823,137643-211684,33-47,16210-28409,748488-837584,1381-2281,1-19 diff --git a/src/day02.scala b/src/day02.scala new file mode 100644 index 0000000..063ee58 --- /dev/null +++ b/src/day02.scala @@ -0,0 +1,46 @@ +package aoc +package day02 + +import scala.annotation.tailrec + +val dayNumber = "02" + +@main def part1: Unit = + println(part1(loadInput(dayNumber))) + +@main def part2: Unit = + println(part2(loadInput(dayNumber))) + +def part1(input: String): String = + + def isValid(id: String): Boolean = + if id.length % 2 == 0 then + val (left, right) = id.splitAt(id.length / 2) + left != right + else true + + input + .split(",") + .map { case s"$from-$to" => from.toLong to to.toLong } + .map(_.filterNot(id => isValid(id.toString)).sum) + .sum + .toString + +def part2(input: String): String = + + def isValid(id: Long): Boolean = + @tailrec + def rec(id: String, groupsCount: Int): Boolean = + if groupsCount < 1 then true + else if id.length % groupsCount == 0 then + id.grouped(groupsCount).distinct.length > 1 && rec(id, groupsCount - 1) + else rec(id, groupsCount - 1) + + rec(id.toString, id.toString.length - 1) + + input + .split(",") + .map { case s"$from-$to" => from.toLong to to.toLong } + .map(_.filterNot(isValid).sum) + .sum + .toString