URL

https://leetcode.com/problems/binary-tree-postorder-traversal/description/?envType=daily-question&envId=2024-08-25

Code

https://github.com/syohex/dotnet-study/blob/master/fsharp/leetcode/challenge/202408/binary_tree_postorder_traversal/main.fsx

type Tree =
    | Leaf
    | Node of int * Tree * Tree

let postorderTraversal (root: Tree) : int list =
    let rec postOrderTraversal' node acc =
        match node with
        | Leaf -> acc
        | Node(v, left, right) ->
            let acc = postOrderTraversal' left acc
            let acc = postOrderTraversal' right acc
            v :: acc

    postOrderTraversal' root [] |> List.rev