题目链接
难度：中等 类型： 二叉树
给定一棵二叉树，想象自己站在它的右侧，按照从顶部到底部的顺序，返回从右侧所能看到的节点值。
示例
输入: [1,2,3,null,5,null,4]
输出: [1, 3, 4]
解题思路
层序遍历，输出每层的最后一个
图片来源https://leetcode-cn.com/problems/binary-tree-right-side-view/solution/er-cha-shu-de-you-shi-tu-by-leetcode/
代码实现
# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class Solution:
def rightSideView(self, root: TreeNode) -> List[int]:
view = []
if root:
level = [root]
while level:
view.append(level[-1].val)
level = [kid for node in level for kid in (node.left, node.right) if kid]
return view
