82 lines
2.9 KiB
Forth
82 lines
2.9 KiB
Forth
module advent_of_code.tasks.day_8.Star1
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open System
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open System.IO
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let stream = new StreamReader("tasks/day-8/input.txt")
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type Point3D =
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struct
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val X: float
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val Y: float
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val Z: float
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new(s: string) =
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let splitS = s.Split(',') |> Array.map float
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let x, y, z = splitS[0], splitS[1], splitS[2]
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{ X = x; Y = y; Z = z }
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member this.GetDistanceFrom(p: Point3D) =
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((p.X - this.X) ** 2 + (p.Y - this.Y) ** 2 + (p.Z - this.Z) ** 2) |> sqrt
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override this.ToString() =
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$"Point3D X = {this.X} Y = {this.Y} Z = {this.Z}"
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end
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type DisjointSet =
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struct
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val Parent: Map<Point3D, Point3D>
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val Size: Map<Point3D, int>
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new(parent: Map<Point3D, Point3D>, size: Map<Point3D, int>) =
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{
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Parent = parent
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Size = size
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}
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new(points: Point3D array) =
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{
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Parent = points |> Array.fold (fun (map: Map<Point3D, Point3D>) (point: Point3D) -> map.Add(point, point)) Map.empty
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Size = points |> Array.fold (fun (map: Map<Point3D, int>) (point: Point3D) -> map.Add(point, 1)) Map.empty
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}
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member this.Find (point: Point3D) =
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let p2 = this.Parent[point]
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if (p2 = point) then
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this, point
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else
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let disjoint, p = this.Find p2
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let parent = disjoint.Parent.Add(point, p)
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DisjointSet(parent, this.Size), p
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member this.Union (connection: Point3D * Point3D) =
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let p1, p2 = connection.Deconstruct()
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let disjointSet, p1 = this.Find(p1)
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let disjointSet, p2 = disjointSet.Find(p2)
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if p1 = p2 then
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disjointSet
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else
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let parent = disjointSet.Parent.Add(p2, p1)
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let size = disjointSet.Size.Add(p1, disjointSet.Size[p1] + disjointSet.Size[p2]).Add(p2, 0)
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DisjointSet(parent, size)
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end
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let connectionFilter (ci: (Point3D * Point3D) * int) =
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let c, i = ci.Deconstruct()
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let p1, p2 = c.Deconstruct()
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i % 2 = 0 && p1.GetDistanceFrom p2 <> 0
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let removeIndex (ci: (Point3D * Point3D) * int) =
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let c, _ = ci.Deconstruct()
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c
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let sortKey (c: Point3D * Point3D) =
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let p1, p2 = c.Deconstruct()
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p1.GetDistanceFrom p2
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let main =
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let points = stream.ReadToEnd().Split('\n') |> Array.map Point3D
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let connections = ((Array.allPairs points points) |> Array.sortBy sortKey |> Array.mapi (fun i el -> el, i) |> Array.filter connectionFilter |> Array.map removeIndex)[.. 999]
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let disjointSet = DisjointSet(points)
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let completeDS = connections |> Array.fold (fun (ds: DisjointSet) (connection: Point3D * Point3D) -> ds.Union(connection)) disjointSet
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let sizes = completeDS.Size.Values |> Seq.sort |> Array.ofSeq
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Array.Reverse sizes
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sizes[..2] |> Array.fold (*) 1
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