Day 25

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

@@ -25,7 +25,8 @@ val solvers = Map[Int, Solver](
   20 -> Day20,
   21 -> Day21,
   22 -> Day22,
-  23 -> Day23
+  23 -> Day23,
+  25 -> Day25
 )
 
 def runSolver(solver: Solver, input: os.Path): Unit =
@@ -36,7 +37,9 @@ def runSolver(solver: Solver, input: os.Path): Unit =
       println(solution.p2)
     case None =>
       println(f"=============================================================")
-      println(f"Day ${solver.day}%02d ------------------------------------------------------")
+      println(
+        f"Day ${solver.day}%02d ------------------------------------------------------"
+      )
       println(f"Prep ${timings.prep}%53s μs")
       println(f"Part 1 ${solution.p1}%40s ${timings.p1}%10s μs")
       println(f"Part 2 ${solution.p2}%40s ${timings.p2}%10s μs")

aoc/src/dev/ctsk/aoc/days/Day25.scala

@@ -0,0 +1,35 @@
+package dev.ctsk.aoc.days
+
+import dev.ctsk.aoc.*
+import collection.parallel.CollectionConverters.*
+
+object Day25 extends Solver(25):
+  override def run(input: os.ReadablePath): (Timings, Solution) =
+    val (pre_time, (locks, keys)) = timed {
+      os
+        .read(input)
+        .split("\n\n")
+        .map(_.linesIterator.map(_.toArray).toArray.transpose)
+        .partition(_(0)(0) == '#')
+    }
+
+    def profile(lock: Array[Array[Char]]): (Array[Int], Int) =
+      (lock.map(_.count(_ == '#')), lock.head.length)
+
+    def fits(size: Int, lock: Array[Int], key: Array[Int]): Boolean =
+      lock.zip(key).forall((l, k) => l + k <= size)
+
+    def p1 = timed {
+      val keyProfiles = keys.map(profile)
+      locks
+        .map(profile)
+        .map((lock, size) =>
+          keyProfiles.count((key, _) => fits(size, lock, key))
+        )
+        .sum
+    }
+
+    (
+      Timings(pre_time, p1._1, 0),
+      Solution(Int.box(p1._2), "MERRY CHRISTMAS")
+    )

data/25.ans

@@ -0,0 +1 @@
+3395