[LeetCode] 199. Binary Tree Right Side View

轉自LeetCode

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].

<Solution>
這題可以看做 Binary Tree Level Order Traversal 的衍生題

利用同樣思路解即可，主要變動的地方是

• 每次 iteration，把 queue 裡面的最後一個 node，放到答案裡面

code 如下