2024: Use HashSet for speeding up

From 30 to 6 seconds... still slow but already a lot better.
jp7677 · Dec 11, 2024 · 2b6e825 · 2b6e825
1 parent 5958099
commit 2b6e825
Showing 1 changed file with 5 additions and 4 deletions.
diff --git a/2024/src/Day06.fs b/2024/src/Day06.fs
@@ -1,5 +1,6 @@
 namespace Aoc2024
 
+open System.Collections.Generic
 open Xunit
 open FsUnit.Xunit
 open Util
@@ -122,7 +123,7 @@ module Day06 =
 
         distinctSteps |> should equal 5212
 
-    [<Fact(Skip = "Slow")>]
+    [<Fact>]
     let ``part 02`` () =
         let max, obstructions, guard = getMap
 
@@ -136,16 +137,16 @@ module Day06 =
                 if obstructions.Contains(newObstruction) || newObstruction = guard.coord then
                     None
                 else
-                    let alternativeObstructions = obstructions |> Set.add newObstruction
+                    let alternativeObstructions = obstructions.Add newObstruction
                     let alternativeSteps = getSteps max alternativeObstructions guard
 
-                    let mutable alternativeGuardStepsSet: Set<Guard> = Set.empty
+                    let alternativeGuardStepsSet = HashSet<Guard>()
 
                     let findRepeat =
                         alternativeSteps
                         |> Seq.tryFind (fun alternativeStep ->
                             let foundRepeatedStep = alternativeGuardStepsSet.Contains(alternativeStep)
-                            alternativeGuardStepsSet <- alternativeGuardStepsSet |> Set.add alternativeStep
+                            alternativeGuardStepsSet.Add alternativeStep |> ignore
                             foundRepeatedStep)
 
                     match findRepeat with