Binary Tree Right Side View

最新推荐文章于 2021-09-10 15:44:05 发布

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本文介绍如何通过迭代方法实现获取给定二叉树的右视图节点值，从顶层到底层顺序返回可见节点。具体实现包括初始化队列、遍历二叉树并记录每一层的最后一个节点值。

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].

class Solution:
    # @param root, a tree node
    # @return a list of integers
    def rightSideView(self, root):
        queue1 = []
        queue2 = []
        last_val_list = []
        
        if(root is None):
            return []
         
        queue1.append(root)   

        while queue1:
            root = queue1[0]
            if root.left is not None:
                queue2.append(root.left)
            if root.right is not None:
                queue2.append(root.right)

            last_val = root.val
            del queue1[0]
              
            if queue1 == []:
                queue1 = queue2
                queue2= []
                last_val_list.append(last_val)
            
        
        return last_val_list