Definition for a binary tree node.

# Definition for a binary tree node.# class TreeNode:#     def __init__(self, val=0, left=None, right=None):#         self.val = val#         self.left = left#         self.right = rightclass Solution:    def rightSideView(self, root: Optional[TreeNode]) -> List[int]:        answer = []        queue = []        if root:            queue.append(root)        while queue:            answer.append(queue[-1].val)            n = len(queue)            for _ in range(n):                node = queue.pop(0)                if node.left:                    queue.append(node.left)                if node.right:                    queue.append(node.right)        return answer