✨ day 15 part 2

twentylemon · Dec 15, 2024 · 644f258 · 644f258
1 parent 728b221
commit 644f258
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Showing 2 changed files with 13 additions and 25 deletions.
diff --git a/src/main/scala/org/lemon/advent/year2024/Day15.scala b/src/main/scala/org/lemon/advent/year2024/Day15.scala
@@ -24,41 +24,31 @@ private object Day15:
     (Coord.gridToMap(wide), parseMoves(moves))
 
   def step(grid: Map[Coord, Char], robit: Coord, dir: Direction): Map[Coord, Char] =
-    println(s"robit = $robit  moving = $dir")
-
     val moves = Iterator.unfold(Set(robit)) { moving =>
-      println(s"moving = $moving")
       if moving.isEmpty then None
       else
         val nexts = moving.map(_ + dir)
-        println(s"nexts = $nexts")
         val boxes = nexts.flatMap(p =>
           grid(p) match
             case 'O' => Seq(p)
             case '[' => Seq(p, p.right)
             case ']' => Seq(p.left, p)
             case _ => Seq()
         ).filterNot(moving)
-        println(s"boxes = $boxes")
         Some(moving -> boxes)
     }.toSeq
 
-    println(s"moves = $moves")
-    val ret =
-      if moves.isEmpty then grid
+    if moves.isEmpty then grid
+    else
+      val dest = moves.flatten.map(_ + dir)
+      if dest.exists(grid(_) == '#') then grid
       else
-        val dest = moves.last.map(_ + dir)
-        if dest.exists(grid(_) == '#') then grid
-        else
-          val gapsFilled = moves.foldLeft(grid) { (g, moving) =>
-            moving.foldLeft(g) { (g, coord) => g.updated(coord, '.') }
-          }
-          moves.foldLeft(gapsFilled) { (g, moving) =>
-            moving.foldLeft(g) { (g, coord) => g.updated(coord + dir, grid(coord)) }
-          }
-
-    println(Area(ret).show(ret))
-    ret
+        val gapsFilled = moves.foldLeft(grid) { (g, moving) =>
+          moving.foldLeft(g) { (g, coord) => g.updated(coord, '.') }
+        }
+        moves.foldLeft(gapsFilled) { (g, moving) =>
+          moving.foldLeft(g) { (g, coord) => g.updated(coord + dir, grid(coord)) }
+        }
 
   def gps(grid: Map[Coord, Char], box: Char) =
     grid.filter(_._2 == box).keysIterator.map(c => 100 * c.y + c.x).sum
@@ -70,6 +60,5 @@ private object Day15:
 
   def part2(input: String) =
     val (grid, moves) = parseWide(input)
-    println(Area(grid).show(grid))
     val last = moves.foldLeft(grid)((g, d) => step(g, g.find(_._2 == '@').get._1, d))
     gps(last, '[')
diff --git a/src/test/scala/org/lemon/advent/year2024/Day15Test.scala b/src/test/scala/org/lemon/advent/year2024/Day15Test.scala
@@ -86,7 +86,6 @@ class Day15Test extends UnitTest:
     part2(in) shouldBe 9021
   }
 
-// test("part 2") {
-//   part2(read(file(2024)(15))) should be > 1463651
-//   part2(read(file(2024)(15))) shouldBe 0
-// }
+  test("part 2") {
+    part2(read(file(2024)(15))) shouldBe 1472235
+  }