let bucketSort unsortedList =
    let rec findCountOf key list =
        match list with
        |[] -> 0
        |(k,v)::tail ->
            match k with
            |k when k = key -> v
            |_ -> (findCountOf key tail)
    List.init
        (List.max unsortedList + 1)
        (fun i -> List.init (findCountOf i (List.countBy id unsortedList)) (fun e -> i))
        |> List.concat

let list = [1;5;7;8;3;43;51;4;6;43]
printfn "%A" (bucketSort list)