1 files changed, 10 insertions, 18 deletions
diff --git a/aoc-2022-dotnet/Day09/Program.fs b/aoc-2022-dotnet/Day09/Program.fs
index 5f49c63..df9f040 100644
--- a/aoc-2022-dotnet/Day09/Program.fs
+++ b/aoc-2022-dotnet/Day09/Program.fs
@@ -1,16 +1,10 @@
 module Day09
 
 open System.IO
-
-type Vec2D =
-    | Vec2D of int * int
-    static member zero = Vec2D(0, 0)
-    static member (+)(Vec2D (x1, y1), Vec2D (x2, y2)) = Vec2D(x1 + x2, y1 + y2)
-    static member (-)(Vec2D (x1, y1), Vec2D (x2, y2)) = Vec2D(x1 - x2, y1 - y2)
-    static member chebyshevDist (Vec2D (x1, y1)) (Vec2D (x2, y2)) = max (abs <| x2 - x1) (abs <| y2 - y1)
+open Common
 
 let directionToVec =
-    Vec2D
+    Vec2
     << function
         | 'U' -> (0, 1)
         | 'R' -> (1, 0)
@@ -19,28 +13,26 @@ let directionToVec =
         | char -> failwithf "Invalid direction: %c" char
 
 let parseHeadMoves =
-    Seq.collect (fun (line: string) -> List.replicate (int line[2..]) (directionToVec line[0]))
+    Seq.collect (fun (line: string) -> Seq.replicate (int line[2..]) (directionToVec line[0]))
 
-let constrainTail head tail =
-    if Vec2D.chebyshevDist head tail <= 1 then
+let moveTail head tail =
+    if Vec2.chebyshevDist head tail <= 1 then
         tail
     else
-        let (Vec2D (dx, dy)) = head - tail
-        tail + Vec2D(sign dx, sign dy)
+        tail + Vec2.sign (head - tail)
 
-let createRope length = List.replicate length Vec2D.zero
+let createRope length = List.replicate length Vec2.zero
 
 let solution ropeLength =
     parseHeadMoves
     >> Seq.scan
-        (fun rope move ->
+        (fun rope headMove ->
             match rope with
-            | h :: t -> List.scan constrainTail (h + move) t
+            | head :: tail -> List.scan moveTail (head + headMove) tail
             | [] -> [])
         (createRope ropeLength)
     >> Seq.map Seq.last
-    >> Set
-    >> Set.count
+    >> Util.countDistinct
 
 let test = File.ReadLines("test.txt")
 assert (solution 2 test = 13)