Solved day 10

README.md

@@ -25,7 +25,7 @@ _My solutions to the 2024 edition of [Advent of Code](https://adventofcode.com/2
 | **[07](https://adventofcode.com/2024/day/7)** | [solution](src/main/scala/adventofcode/solutions/Day07.scala) |
 | **[08](https://adventofcode.com/2024/day/8)** | [solution](src/main/scala/adventofcode/solutions/Day08.scala) |
 | **[09](https://adventofcode.com/2024/day/9)** | [solution](src/main/scala/adventofcode/solutions/Day09.scala) |
-| **[10](https://adventofcode.com/2024/day/10)** | [](src/main/scala/adventofcode/solutions/Day10.scala) |
+| **[10](https://adventofcode.com/2024/day/10)** | [solution](src/main/scala/adventofcode/solutions/Day10.scala) |
 | **[11](https://adventofcode.com/2024/day/11)** | [](src/main/scala/adventofcode/solutions/Day11.scala) |
 | **[12](https://adventofcode.com/2024/day/12)** | [](src/main/scala/adventofcode/solutions/Day12.scala) |
 | **[13](https://adventofcode.com/2024/day/13)** | [](src/main/scala/adventofcode/solutions/Day13.scala) |

input/10.txt

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output/10-1.txt

@@ -0,0 +1 @@
+698

output/10-2.txt

@@ -0,0 +1 @@
+1436

src/main/scala/adventofcode/solutions/Day10.scala

@@ -0,0 +1,39 @@
+package adventofcode.solutions
+
+import adventofcode.Definitions.*
+
+@main def Day10 = Day(10) { (input, part) =>
+
+  case class Vec(i: Int, j: Int):
+    infix def +(that: Vec): Vec = Vec(i + that.i, j + that.j)
+
+  val grid = input.toLines.map(_.map(_.asDigit))
+
+  val zeros = grid.indices.flatMap(i => grid(i).indices.filter(j => grid(i)(j) == 0).map(j => Vec(i, j)))
+
+  val adjacent =
+    for
+      i <- -1 to 1
+      j <- -1 to 1
+      if i.abs + j.abs == 1
+    yield Vec(i, j)
+
+  def inBounds(vec: Vec): Boolean = grid.indices.contains(vec.i) && grid(vec.i).indices.contains(vec.j)
+
+  def explore(nodes: Iterable[Vec], i: Int): Int =
+    if i < 10 then
+      val nextNodes = nodes
+        .flatMap(n => adjacent.map(n + _))
+        .filter(inBounds)
+        .filter(v => grid(v.i)(v.j) == i)
+      explore(nextNodes, i + 1)
+    else
+      nodes.size
+
+  def count(factory: Vec => Iterable[Vec]): Int = zeros.map(zero => explore(factory(zero), 1)).sum
+
+  part(1) = count(Set.apply(_))
+
+  part(2) = count(Seq.apply(_))
+
+}