Finish last exercise from 2022

1 files changed, 94 insertions, 0 deletions

diff --git a/aoc-2022-dotnet/Day22/Program.fs b/aoc-2022-dotnet/Day22/Program.fs
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+module Day22
+
+open System.IO
+open System.Text.RegularExpressions
+open FSharpPlus
+open FSharpPlus.Math.Generic
+open Common
+
+let passwordRegex = Regex("L|R|\d+", RegexOptions.Compiled)
+
+let facing =
+    function
+    | Vec2 (1, 0) -> 0
+    | Vec2 (0, 1) -> 1
+    | Vec2 (-1, 0) -> 2
+    | Vec2 (0, -1) -> 3
+    | v -> failwithf "Invalid direction: %A" v
+
+let solution wrapper input =
+    let map, password = Util.splitStringToTuple "\n\n" input
+
+    let map =
+        map
+        |> String.split [ "\n" ]
+        |> Seq.map (String.padRight 150)
+        |> array2D
+
+    let (pos, dir) =
+        passwordRegex.Matches(password)
+        |> Seq.fold
+            (fun (pos, dir) c ->
+                match c.Value with
+                | "R" -> pos, Vec2.rotateLeft dir
+                | "L" -> pos, Vec2.rotateRight dir
+                | dist ->
+                    Util.composition
+                        (int dist)
+                        (fun state ->
+                            let state' = state |> mapItem1 ((+) <| snd state) |> wrapper
+
+                            match Util.mAt map (fst state') with
+                            | '.' -> state'
+                            | _ -> state)
+                        (pos, dir))
+            (Vec2(Seq.findIndex ((=) '.') map[0, *], 0), Vec2.right)
+
+    let (Vec2 (x, y)) = pos + Vec2.ones
+    y * 1000 + x * 4 + facing dir
+
+let wrap1 (Vec2 (x, y), d) =
+    let x, y =
+        match (divE x 50, divE y 50, d) with
+        | (1, 3, Vec2 (0, 1))
+        | (2, 1, Vec2 (0, 1)) -> x, 0
+        | (2, -1, Vec2 (0, -1)) -> x, 49
+        | (0, 4, Vec2 (0, 1)) -> x, 100
+        | (1, -1, Vec2 (0, -1)) -> x, 149
+        | (0, 1, Vec2 (0, -1)) -> x, 199
+        | (1, 3, Vec2 (1, 0))
+        | (2, 2, Vec2 (1, 0)) -> 0, y
+        | (-1, 3, Vec2 (-1, 0)) -> 49, y
+        | (2, 1, Vec2 (1, 0))
+        | (3, 0, Vec2 (1, 0)) -> 50, y
+        | (-1, 2, Vec2 (-1, 0))
+        | (0, 1, Vec2 (-1, 0)) -> 99, y
+        | (0, 0, Vec2 (-1, 0)) -> 149, y
+        | _ -> x, y
+
+    Vec2(x, y), d
+
+let wrap2 (Vec2 (x, y), d) =
+    let x, y, t =
+        match (divE x 50, divE y 50, d) with
+        | (-1, 2, Vec2 (-1, 0)) -> 50, 149 - y, Vec2.flip
+        | (-1, 3, Vec2 (-1, 0)) -> y - 100, 0, Vec2.rotateRight
+        | (0, 0, Vec2 (-1, 0)) -> 0, 149 - y, Vec2.flip
+        | (0, 1, Vec2 (-1, 0)) -> y - 50, 100, Vec2.rotateRight
+        | (0, 1, Vec2 (0, -1)) -> 50, x + 50, Vec2.rotateLeft
+        | (0, 4, Vec2 (0, 1)) -> x + 100, 0, id
+        | (1, -1, Vec2 (0, -1)) -> 0, x + 100, Vec2.rotateLeft
+        | (1, 3, Vec2 (1, 0)) -> y - 100, 149, Vec2.rotateRight
+        | (1, 3, Vec2 (0, 1)) -> 49, x + 100, Vec2.rotateLeft
+        | (2, -1, Vec2 (0, -1)) -> x - 100, 199, id
+        | (2, 1, Vec2 (1, 0)) -> y + 50, 49, Vec2.rotateRight
+        | (2, 1, Vec2 (0, 1)) -> 99, x - 50, Vec2.rotateLeft
+        | (2, 2, Vec2 (1, 0)) -> 149, 149 - y, Vec2.flip
+        | (3, 0, Vec2 (1, 0)) -> 99, 149 - y, Vec2.flip
+        | _ -> x, y, id
+
+    Vec2(x, y), t d
+
+let input = File.ReadAllText("input.txt")
+printfn "%b" (solution wrap1 input = 103224)
+printfn "%b" (solution wrap2 input = 189097)