open System
open System.Diagnostics
open System

let getNextSequential n =
    let r = Random 42
    let start = r.Next (n*3/2)
    fun i -> (start + i) % n

let getNextRandom n =
    let r = Random 42
    fun _ -> r.Next (n*4)

[<EntryPoint>]
let main argv =
    let f =
        match argv with
        | [| "sequential" |] -> getNextSequential
        | [| "random" |]     -> getNextRandom
        | _ -> failwith "invalid arg"

    for i in 0 .. 25 .. 250 do
        let getNext = f i

        let elementsA = Array.init i getNext
        let elementsB = Array.init i getNext

        let sw = Stopwatch.StartNew ()
        for j = 1 to 1000000 / (i+1) do
            let a = Set.ofArray elementsA
            let b = Set.ofArray elementsB
            let c = Set.union a b
            for a in elementsA do
                if not (c |> Set.contains a) then failwith "boom"
            for b in elementsB do
                if not (c |> Set.contains b) then failwith "boom"

        printfn "%s,%s,%d,%d" argv.[0] (if Environment.Is64BitProcess then "64-bit" else "32-bit") i sw.ElapsedMilliseconds

    0 // return an integer exit code