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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"
|