首页 > itarticle > leetcode199: binary tree right side view 2. Analysis 3. Solution(s)

leetcode199: binary tree right side view 2. Analysis 3. Solution(s)

admin 11月 12, 2020 0

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].

2. Analysis

3. Solution(s)

# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
class (object):
    def rightSideView(self, root):
        """
        :type root: TreeNode
        :rtype: List[int]
        """
        if not root: return list()
        res, level = list(), [root]
        while level:
            res.append(level[-1].val)
            tmp = list()
            for node in level:
                tmp.append(node.left)
                tmp.append(node.right)
            level = [x for x in tmp if x] # filter None node
        return res