let part1 =
    [ for a in arr do
        for b in arr do
            if a + b = 2020 then
                (a * b) ]

let tupleToArray2 t =
    match t with
    | (a, b) -> [| a; b |]
let tupleToArray3 t =
    match t with
    | (a, b, c) -> [| a; b; c |]

let part2 =
    [ for a in arr do

let part1 (arr: int list) = query {
    for a in arr do
        for b in arr do
            find (a + b = 2020)
}
let part2 (arr: int list) = query {
    for a in arr do

                if a + b + c = 2020 then
                    (a * b * c) ]

                find (a + b + c = 2020)
}

    printfn "%d" part1.[0]
    printfn "%d" part2.[0]
    0 // return an integer exit code

    let v = part1 arr |> tupleToArray2 |> Array.reduce (*)
    printfn "%d" v
    let v2 = part2 arr |> tupleToArray3 |> Array.reduce (*)
    printfn "%d" v2
    0