Given the `root` of a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom.

Example 1:

    Input: root = [1,2,3,null,5,null,4]
    Output: [1,3,4]

Example 2:

    Input: root = [1,null,3]
    Output: [1,3]

Example 3:

    Input: root = []
    Output: []

Constraints:

- The number of nodes in the tree is in the range `[0, 100]`.
- `-100 <= Node.val <= 100`