1 files changed, 51 insertions, 0 deletions
diff --git a/day2.fsx b/day2.fsx
new file mode 100644
index 0000000..26fc704
--- /dev/null
+++ b/day2.fsx
@@ -0,0 +1,51 @@
+open System.IO
+
+let keypad1 (pos: int * int): string = 
+    let (x, y) = pos
+    string (x + 3 * y + 1)
+
+let keypad2 (pos: int * int): string =
+    let pad = [
+        "--1--"
+        "-234-"
+        "56789"
+        "-ABC-"
+        "--D--"
+    ]
+    let (row, col) = pos
+    string (pad[col][row])
+
+let final_pos1 (start: int * int) (line: string) =
+    let move (pos: int*int) (dPos: char) = 
+        let (x, y) = pos
+        match dPos with
+            | 'U' -> (x, y-1 |> max 0 |> min 2)
+            | 'D' -> (x, y+1 |> max 0 |> min 2)
+            | 'L' -> (x-1 |> max 0 |> min 2, y)
+            | 'R' -> (x+1 |> max 0 |> min 2, y)
+            | _ -> (-500, -500)
+    List.fold move start (Seq.toList line)
+
+let final_pos2 (start: int*int) (line: string) =
+    let move (pos: int*int) (dPos: char) =
+        let (x, y) = pos
+        let newPos =
+            match dPos with
+                | 'U' -> (x, y-1 |> max 0 |> min 4)
+                | 'D' -> (x, y+1 |> max 0 |> min 4)
+                | 'L' -> (x-1 |> max 0 |> min 4, y)
+                | 'R' -> (x+1 |> max 0 |> min 4, y)
+                | _ -> (-500, -500)
+        if keypad2 newPos = "-" then pos else newPos
+    List.fold move start (Seq.toList line)
+
+let lines = "day2.txt" |> File.ReadLines |> Seq.toList
+
+let generate_code (instructions: list<string>) (posfunc: int*int -> string -> int*int) (keyfunc: int*int -> string) (start: int*int): list<string> =
+    let positions = List.scan posfunc start instructions
+    List.map keyfunc positions[1..]
+
+// part 1
+generate_code lines final_pos1 keypad1 (1, 1) |> String.concat "" |> printfn "%s"
+// part 2
+generate_code lines final_pos2 keypad2 (0, 2) |> String.concat "" |> printfn "%s"
\ No newline at end of file