async

open System
open System.IO
open System.Diagnostics

let path = @"C:\Users\juegest\"
let parse s = ()

let calc x coef =
    let res, _, _ =
        coef
        |> Array.fold
            (fun (r, d, pow) k ->
                let npow = pow * x
                (r + (k * npow) / d, d + 1., npow) ) (0., 1., 1.)
    res

let awaitTask = Async.AwaitIAsyncResult >> Async.Ignore
let processAllFiles n =
    seq { for i in 1 .. n -> async {
            let in_filename = path + @"inp" + string i + ".txt"
            let out_filename = path + @"out" + string i + ".txt"
            use fin = File.OpenRead(in_filename)
            use sr = new StreamReader(fin)
            let! s = sr.ReadLineAsync() |> Async.AwaitTask
            let coef =
                s.Split([| ' ' |], StringSplitOptions.RemoveEmptyEntries)
                |> Array.map float
                |> Array.rev
            let! s = sr.ReadLineAsync() |> Async.AwaitTask
            let lims = s.Split([| ' ' |], StringSplitOptions.RemoveEmptyEntries) |> Array.map float
            let a, b = lims.[0], lims.[1]
            let result = (calc a coef - calc b coef) |> string
            use fout = File.OpenWrite(out_filename)
            use sw = new StreamWriter(fout)
            do! sw.WriteLineAsync(result) |> awaitTask
        }
    }
    |> Async.Parallel
    |> Async.RunSynchronously
    |> ignore


[<EntryPoint>]
let main argv =
    let sw = new Stopwatch()
    sw.Start()
    processAllFiles 3
    sw.Stop()
    printfn "Done (time: %f)" (float sw.ElapsedMilliseconds / 1000.)
    System.Console.ReadKey() |> ignore
    0 // возвращение целочисленного кода выхода