Day 16: Early exit search loop

aoc/src/dev/ctsk/aoc/Main.scala

@@ -31,6 +31,7 @@ val solvers = Map[Int, Solver](
 )
 
 def runSolver(solver: Solver, input: os.Path): Unit =
+  for _ <- 0 to 100 do solver.run(input)
   val (timings, solution) = solver.run(input)
   sys.env.get("AOC_BENCH") match
     case Some(_) =>

aoc/src/dev/ctsk/aoc/days/Day16.scala

@@ -3,6 +3,8 @@ package dev.ctsk.aoc.days
 import dev.ctsk.aoc.{Direction, *}
 
 import scala.collection.mutable
+import scala.util.boundary
+import scala.util.boundary.break
 
 object Day16 extends Solver(16):
   override def run(input_ : os.ReadablePath): (Timings, Solution) =
@@ -14,7 +16,6 @@ object Day16 extends Solver(16):
     val end = grid.findFirst(_ == 'E').get
 
     case class State(distance: Int, pose: Pose)
-    implicit def ord: Ordering[State] = Ordering.by(-1 * _.distance)
 
     def search(start: Pose): (Map[Pose, Int], Map[Pose, List[Pose]]) =
       val distance = mutable.Map(start -> 0)
@@ -32,18 +33,23 @@ object Day16 extends Solver(16):
           then far.push(State(vDist, v))
           else near.push(State(vDist, v))
 
-      while near.nonEmpty do
+      boundary:
         while near.nonEmpty do
-          val State(uDist, u) = near.pop()
-          if uDist == distance(u) then
-            if !grid(u.step.pos).contains('#') then
-              relax(u, u.step, uDist + 1, false)
-            for (v <- Seq(u.turnLeft, u.turnRight)) do
-              relax(u, v, uDist + 1000, true)
+          var atEnd = false;
+          while near.nonEmpty do
+            val State(uDist, u) = near.pop()
+            atEnd |= u.pos == end
+            if uDist == distance(u) then
+              if !grid(u.step.pos).contains('#') then
+                relax(u, u.step, uDist + 1, false)
+              for (v <- Seq(u.turnLeft, u.turnRight)) do
+                relax(u, v, uDist + 1000, true)
 
-        val tmp = near
-        near = far
-        far = tmp
+          if atEnd then break()
+
+          val tmp = near
+          near = far
+          far = tmp
 
       (distance.toMap, ancestor.toMap)
 
@@ -51,7 +57,7 @@ object Day16 extends Solver(16):
       search(Pose(start, Direction.Right))
     }
 
-    val endPose = DIRS.map(Pose(end, _)).minBy(distance(_))
+    val endPose = DIRS.map(Pose(end, _)).minBy(distance.getOrElse(_, 1_000_000))
 
     val p1 = distance(endPose)