URL

Add to Array-Form of Integer - LeetCode

Code

https://github.com/syohex/dotnet-study/tree/master/fsharp/leetcode/problems/0989/main.fsx

let addToArrayForm (num: int list) (k: int) : int list =
    let rec addToArrayForm' nums ks carry acc =
        match nums, ks with
        | [], [] -> if carry = 1 then 1 :: acc else acc
        | h :: t, [] ->
            let v = h + carry

            if v >= 10 then
                addToArrayForm' t [] 1 ((v - 10) :: acc)
            else
                addToArrayForm' t [] 0 (v :: acc)
        | [], h :: t ->
            let v = h + carry

            if v >= 10 then
                addToArrayForm' [] t 1 ((v - 10) :: acc)
            else
                addToArrayForm' [] t 0 (v :: acc)
        | h1 :: t1, h2 :: t2 ->
            let v = h1 + h2 + carry

            if v >= 10 then
                addToArrayForm' t1 t2 1 ((v - 10) :: acc)
            else
                addToArrayForm' t1 t2 0 (v :: acc)

    let ks = k |> string |> Seq.map (fun c -> int c - int '0') |> Seq.rev |> Seq.toList
    addToArrayForm' (num |> List.rev) ks 0 []