[Leetcode] 199. Binary Tree Right Side View

I referred to this solution: it's really succinct and ingenious. I am a little far from this level of coding.

Given 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.

For example:
Given the following binary tree,

1            <---
 /   \
2     3         <---
 \     \
  5     4       <---

You should return [1, 3, 4].

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution(object):
    def rightSideView(self, root):
        """
        :type root: TreeNode
        :rtype: List[int]
        """
        def collect(node, depth):
            if not node:
                return
            if len(view) == depth:
                view.append(node.val)
            collect(node.right, depth+1)
            collect(node.left, depth+1)
        
        view = []
        collect(root, 0)
        return view