Dump top-down solver stuff

sim642 · Dec 16, 2023 · eab4c00 · eab4c00
1 parent 210de7a
commit eab4c00
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Showing 2 changed files with 80 additions and 47 deletions.
diff --git a/src/main/scala/eu/sim642/adventofcode2023/Day16.scala b/src/main/scala/eu/sim642/adventofcode2023/Day16.scala
@@ -13,50 +13,56 @@ object Day16 {
 
   case class Beam(pos: Pos, direction: Pos)
 
-  def countEnergized(grid: Grid[Char], startBeam: Beam = Beam(Pos.zero, Pos(1, 0))): Int = {
-
-    val graphTraversal = new GraphTraversal[Beam] with UnitNeighbors[Beam] {
-      override val startNode: Beam = startBeam
-
-      override def unitNeighbors(beam: Beam): IterableOnce[Beam] = {
-        val Beam(pos, direction) = beam
-        val newDirections =
-          grid(pos) match {
-            case '.' => Iterator(direction)
-            case '/' => Iterator(direction.reflectMinor)
-            case '\\' => Iterator(direction.reflectMajor)
-            case '|' if direction.x == 0 => Iterator(direction)
-            case '-' if direction.y == 0 => Iterator(direction)
-            case '|' | '-' => Iterator(direction.left, direction.right)
-          }
-        for {
-          newDirection <- newDirections
-          newPos = pos + newDirection
-          if grid.containsPos(newPos)
-        } yield Beam(newPos, newDirection)
-      }
+  def countEnergized0(grid: Grid[Char]): Beam => Int = {
+
+    def unitNeighbors(beam: Beam): IterableOnce[Beam] = {
+      val Beam(pos, direction) = beam
+      val newDirections =
+        grid(pos) match {
+          case '.' => Iterator(direction)
+          case '/' => Iterator(direction.reflectMinor)
+          case '\\' => Iterator(direction.reflectMajor)
+          case '|' if direction.x == 0 => Iterator(direction)
+          case '-' if direction.y == 0 => Iterator(direction)
+          case '|' | '-' => Iterator(direction.left, direction.right)
+        }
+      for {
+        newDirection <- newDirections
+        newPos = pos + newDirection
+        if grid.containsPos(newPos)
+      } yield Beam(newPos, newDirection)
     }
 
     def f(x: Beam)(get: Beam => Set[Pos]): Set[Pos] =
-      //graphTraversal.unitNeighbors(x).iterator.flatMap(get).toSet + x.pos
-      graphTraversal.unitNeighbors(x).iterator.map(get).foldLeft(Set.empty[Pos])(_ ++ _) + x.pos
+      //unitNeighbors(x).iterator.flatMap(get).toSet + x.pos
+      unitNeighbors(x).iterator.map(get).foldLeft(Set.empty[Pos])(_ ++ _) + x.pos
 
     val stable = mutable.Set.empty[Beam]
     val called = mutable.Set.empty[Beam]
-    val infl = mutable.Map.empty[Beam, Set[Beam]].withDefaultValue(Set.empty[Beam])
+    val infl = mutable.Map.empty[Beam, mutable.Set[Beam]].withDefault(_ => mutable.Set.empty[Beam])
     val rho = mutable.Map.empty[Beam, Set[Pos]].withDefaultValue(Set.empty[Pos])
 
+    var indent = 0
+
     def destabilize(x: Beam): Unit = {
+      println(s"${" " * indent}destab $x")
       val w = infl(x)
-      infl(x) = Set.empty
+      //infl(x) = Set.empty
+      infl.remove(x)
       for (y <- w) {
+        println(s"${" " * indent}stable remove $y")
         stable -= y
-        if (!called(y))
+        if (!called(y)) {
+          indent += 1
           destabilize(y)
+          indent -= 1
+        }
       }
     }
 
     def eval(x: Beam)(y: Beam): Set[Pos] = {
+      //infl(y) += x
+      //solve(y)
       solve(y)
       infl(y) += x
       rho(y)
@@ -65,37 +71,71 @@ object Day16 {
 
     @tailrec
     def solve(x: Beam): Unit = {
-      println((rho.size, stable.size, called.size))
+      println(s"${" " * indent}solve $x")
+      //println((rho.size, stable.size, called.size))
       if (!stable(x) && !called(x)) {
-        stable += x
+        //println(s"${" " * indent}stable add $x")
+        //stable += x
         called += x
+        indent += 1
         //val tmp = rho(x) union f(x)(eval(x))
         val tmp = f(x)(eval(x))
+        indent -= 1
         called -= x
         if (rho(x) != tmp) {
-          println(s"  ${tmp.size}")
+          //println(s"  ${tmp.size}")
           rho(x) = tmp
           destabilize(x)
+          //stable -= x
           solve(x)
         }
+        else {
+          println(s"${" " * indent}stable add $x")
+          stable += x
+        }
+      }
+      else if (!called(x)) {
+        assert(stable(x))
+        called += x
+        indent += 1
+        //val tmp = rho(x) union f(x)(eval(x))
+        val tmp = f(x)(eval(x))
+        indent -= 1
+        called -= x
+        if (rho(x) != tmp) {
+          val x1 = rho(x) -- tmp
+          val x2 = tmp -- rho(x)
+          println(s"STABLE CHANGE $x $x1 $x2")
+          throw new IllegalStateException()
+        }
       }
     }
 
 
     //println(DFS.traverse(graphTraversal).nodes.size)
     //DFS.traverse(graphTraversal).nodes.map(_.pos).size
 
-    solve(graphTraversal.startNode)
-    //print(rho)
-    rho(graphTraversal.startNode).size
+    beam => {
+      println(s"$beam: ${stable(beam)} ${rho(beam).size} ${stable}")
+      solve(beam)
+      assert(stable(beam))
+      assert(called.isEmpty)
+      //infl.clear()
+      //stable.clear()
+      //print(rho)
+      rho(beam).size
+    }
   }
 
+  def countEnergized(grid: Grid[Char], startBeam: Beam = Beam(Pos.zero, Pos(1, 0))): Int =
+    countEnergized0(grid)(startBeam)
+
   def maxEnergized(grid: Grid[Char]): Int = {
     val top = grid(0).indices.map(x => Beam(Pos(x, 0), Pos(0, 1)))
     val bottom = grid(0).indices.map(x => Beam(Pos(x, grid.size - 1), Pos(0, -1)))
     val left = grid.indices.map(y => Beam(Pos(0, y), Pos(1, 0)))
     val right = grid.indices.map(y => Beam(Pos(grid(0).size - 1, y), Pos(-1, 0)))
-    (top ++ bottom ++ left ++ right).map(countEnergized(grid, _)).max
+    (top ++ bottom ++ left ++ right).map(countEnergized0(grid)).tapEach(println).max
   }
 
 

diff --git a/src/test/scala/eu/sim642/adventofcode2023/Day16Test.scala b/src/test/scala/eu/sim642/adventofcode2023/Day16Test.scala
@@ -6,30 +6,23 @@ import org.scalatest.funsuite.AnyFunSuite
 class Day16Test extends AnyFunSuite {
 
   private val exampleInput =
-    """.|...\....
-      ||.-.\.....
-      |.....|-...
-      |........|.
-      |..........
-      |.........\
-      |..../.\\..
-      |.-.-/..|..
-      |.|....-|.\
-      |..//.|....""".stripMargin
+    """.\.
+      |.-\
+      |.\/""".stripMargin
 
   test("Part 1 examples") {
     assert(countEnergized(parseGrid(exampleInput)) == 46)
   }
 
   test("Part 1 input answer") {
-    assert(countEnergized(parseGrid(input)) == 7067)
+    //assert(countEnergized(parseGrid(input)) == 7067)
   }
 
   test("Part 2 examples") {
-    assert(maxEnergized(parseGrid(exampleInput)) == 51)
+    //assert(maxEnergized(parseGrid(exampleInput)) == 51)
   }
 
   test("Part 2 input answer") {
-    assert(maxEnergized(parseGrid(input)) == 7324)
+    //assert(maxEnergized(parseGrid(input)) == 7324)
   }
 }