URL

https://leetcode.com/problems/non-decreasing-subsequences/description/

Code

https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/problems/0491/main.fsx

let findSubSequences (nums: int list) : int list list =
    let isNotEmpty = List.isEmpty >> not

    let rec findSubSequences' nums acc ret =
        match nums with
        | [] ->
            if isNotEmpty acc && List.tail acc |> isNotEmpty then
                Set.add (acc |> List.rev) ret
            else
                ret
        | h :: t ->
            let ret' = findSubSequences' t acc ret

            match acc with
            | [] -> findSubSequences' t (h :: acc) ret'
            | prev :: _ ->
                if prev <= h then
                    findSubSequences' t (h :: acc) ret'
                else
                    ret'

    findSubSequences' nums [] Set.empty |> Seq.toList