Day 02

src/day02.scala

@@ -0,0 +1,46 @@
+package aoc
+package day02
+
+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 isSafe(rs: Array[Int]): Boolean =
+    val rsInc = if rs.head > rs.last then rs.reverse else rs
+    rsInc
+      .sliding(2)
+      .map { case Array(a, b) => b - a }
+      .forall(diff => diff >= 1 && diff <= 3)
+
+  input
+    .split("\n")
+    .map(_.split(" ").map(_.toInt))
+    .count(isSafe)
+    .toString
+
+def part2(input: String): String =
+
+  def isSafe(rs: Array[Int]): Boolean =
+    val rsInc = if rs.head > rs.last then rs.reverse else rs
+    rsInc
+      .sliding(2)
+      .map { case Array(a, b) => b - a }
+      .forall(diff => diff >= 1 && diff <= 3)
+
+  def isSafeWithTolerance(rs: Array[Int]): Boolean =
+    isSafe(rs) ||
+      (for i <- 0 to rs.length
+      yield isSafe(rs.take(i) ++ rs.drop(i + 1)))
+        .exists(identity)
+
+  input
+    .split("\n")
+    .map(_.split(" ").map(_.toInt))
+    .count(isSafeWithTolerance)
+    .toString