Return right and left side views of a tree

Given the root of a binary tree, compute two “side views”: 1. `right_view`: the list of node values visible when looking at the tree from the **right** side, ordered from **top to bottom**. 2. `left_view_reversed`: the list of node values visible when looking at the tree from the **left** side, but ordered from **bottom to top** (i.e., the left side view, then reversed). Return both lists. ## Definitions - The side view at a given depth is the value of the node you would see from that side (i.e., the last node encountered at that depth when scanning from that side). ## Input - `root`: root node of a binary tree. ## Output - A pair/tuple: `(right_view, left_view_reversed)`. ## Constraints - Number of nodes: `0..2*10^5` - Node values fit in 32-bit signed integer. ## Example Tree: ``` 1 / \ 2 3 \ \ 5 4 ``` - `right_view = [1, 3, 4]` - `left_view = [1, 2, 5]` so `left_view_reversed = [5, 2, 1]`