feat(2024/10): 2024 day 10

2024/day10.scala

@@ -0,0 +1,28 @@
+package `2024`.day10
+
+import prelude.*
+
+case class Context(grid: Grid[Int]):
+  def next(x: Pos): Vector[Pos] =
+    if grid(x) == 9 then Vector(x)
+    else
+      x.neighbours
+        .withFilter(y => grid.size(y) && grid(y) == grid(x) + 1)
+        .flatMap(next)
+
+  lazy val trails = grid.where(_ == 0).map(next)
+  lazy val part1 = trails.sumBy(_.toSet.size)
+  lazy val part2 = trails.sumBy(_.size)
+
+  override def toString = grid.repr
+    .map(xs => xs.map(x => (if x >= 0 then x else '.')).mkString)
+    .mkString("\n")
+
+@main def main() =
+  val input = readInput(this).mkString
+  val ctx = Context(Grid(input).map(_.asDigit))
+
+  println(ctx)
+  println(ctx.grid.size)
+  println(ctx.part1)
+  println(ctx.part2)

2024/day10.test.scala

@@ -0,0 +1,44 @@
+package `2024`.day10
+
+val example1 =
+  """|0123
+     |1234
+     |8765
+     |9876""".stripMargin
+
+val example2 =
+  """|...0...
+     |...1...
+     |...2...
+     |6543456
+     |7.....7
+     |8.....8
+     |9.....9""".stripMargin
+
+val example3 =
+  """|..90..9
+     |...1.98
+     |...2..7
+     |6543456
+     |765.987
+     |876....
+     |987....""".stripMargin
+
+val example4 =
+  """|10..9..
+     |2...8..
+     |3...7..
+     |4567654
+     |...8..3
+     |...9..2
+     |.....01""".stripMargin
+
+val example5 =
+  """|89010123
+     |78121874
+     |87430965
+     |96549874
+     |45678903
+     |32019012
+     |01329801
+     |10456732""".stripMargin