Определите номер первого и последнего максимального элемента последовательности

[1..10] |> Seq.maxBy (fun x -> x%7)

let firsLastMax s =
    let max = Seq.max s
    Seq.findIndex ((=)max) s, Seq.findIndexBack ((=)max) s

seq{1;2;3;2;4;2;1;2;3;1;4;2;1} |> firsLastMax |> printfn "%A"

open System.IO
let maxLenName dirName = Directory.GetFiles(dirName) |> Array.map Path.GetFileName |> Array.maxBy String.length

let firstLastMax s =
    let folder (i1,i2,n1) i n = if n > n1 then i,i,n elif n = n1 then i1,i,n1 else i1,i2,n1
    let state = (0, 0, Seq.head s)
    let indices = Seq.initInfinite id
    let (i1,i2,n) =  Seq.fold2 folder state indices s
    (i1,i2)

open System
[<EntryPoint>]
let main argv =
  
  printfn "%s" "Введите размер последовательности"
  let size = Console.ReadLine() |> int
     
  printfn "%s" "Введите элементы последовательности"
  let seq = Seq.init size (fun _ -> Console.ReadLine() |> int)
  let n = int
 
  let firstLastMax s =
      let folder (i1,i2,n1) i n = if n > n1 then i,i,n elif n = n1 then i1,i,n1 else i1,i2,n1
      let state = (0, 0, Seq.head s)
      let indices = Seq.initInfinite id
      let (i1,i2,n) =  Seq.fold2 folder state indices s
      (i1,i2)
      printfn ("%A") (i1,i2,n)
  0

printfn ("%A") (i1,i2,n)

printfn "%A" <| firstLastMax seq

let seq = List.init size (fun _ -> Console.ReadLine() |> int)

let state = (0, 0, Int32.MinValue)