Day 2

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

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