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].
BFS 每层都以从右向左的顺序扔数组里取出第一个到结果数组中，然后再对下一层同样操作。
class Solution(object): def rightSideView(self, root): if not root: return [] a, ans = [root], [] while a: b = [] ans.append(a[0].val) for node in a: if node.right: b.append(node.right) if node.left: b.append(node.left) a = b return ans
Leetcode 199 Binary Tree Right Side View
原文：http://www.cnblogs.com/lilixu/p/5391245.html