Finish day 17

2 files changed, 28 insertions, 1 deletions

diff --git a/aoc-2022-dotnet/Common/Util.fs b/aoc-2022-dotnet/Common/Util.fs
index acf89af..568f2c2 100644
--- a/aoc-2022-dotnet/Common/Util.fs
+++ b/aoc-2022-dotnet/Common/Util.fs
@@ -38,7 +38,11 @@ module Util =
 
     let mAt matrix (Vec2 (col, row)) = Array2D.get matrix row col
 
-    let composition n f = List.replicate n f |> List.reduce (>>)
+    let rec composition n f x =
+        if n = 0 then
+            x
+        else
+            composition (n - 1) f (f x)
 
     let notIn set element = not <| Set.contains element set
 
@@ -51,6 +55,16 @@ module Util =
         | h :: t -> min h x :: (insertSorted (max h x) t)
         | [] -> [ x ]
 
+    let liftList xs =
+        match List.forall Option.isSome xs with
+        | true -> Some(List.map Option.get xs)
+        | false -> None
+
+    let cycle =
+        function
+        | h :: t -> h, t @ [ h ]
+        | [] -> failwith "Empty list!"
+
     let topN n xs =
         Seq.fold
             (fun acc x ->
diff --git a/aoc-2022-dotnet/Common/Vec2.fs b/aoc-2022-dotnet/Common/Vec2.fs
index 8835a5a..61b313d 100644
--- a/aoc-2022-dotnet/Common/Vec2.fs
+++ b/aoc-2022-dotnet/Common/Vec2.fs
@@ -13,6 +13,8 @@ type Vec2 =
     static member down = Vec2(0, -1)
     static member left = Vec2(-1, 0)
 
+    static member upRight = Vec2(1, 1)
+    static member upLeft = Vec2(-1, 1)
     static member downLeft = Vec2(-1, -1)
     static member downRight = Vec2(1, -1)
 
@@ -22,6 +24,16 @@ type Vec2 =
           Vec2.down
           Vec2.left ]
 
+    static member directions8 =
+        [ Vec2.up
+          Vec2.upRight
+          Vec2.right
+          Vec2.downRight
+          Vec2.down
+          Vec2.downLeft
+          Vec2.left
+          Vec2.upLeft ]
+
     static member inline (~-) = Vec2.map (~-)
     static member inline (+)(Vec2 (x1, y1), Vec2 (x2, y2)) = Vec2(x1 + x2, y1 + y2)
     static member inline (-)(v1, v2) = v1 + Vec2.op_UnaryNegation (v2)
@@ -34,6 +46,7 @@ type Vec2 =
     static member mahattanDist (Vec2 (x1, y1)) (Vec2 (x2, y2)) = abs (x2 - x1) + abs (y2 - y1)
     static member chebyshevDist (Vec2 (x1, y1)) (Vec2 (x2, y2)) = max (abs <| x2 - x1) (abs <| y2 - y1)
     static member neighbours4 v = List.map ((+) v) Vec2.directions4
+    static member neighbours8 v = List.map ((+) v) Vec2.directions8
 
     static member lineBetween(Vec2 (x1, y1), Vec2 (x2, y2)) =
         if x1 = x2 then