Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left to right, level by level from leaf to root).
For example:
Given binary tree {3,9,20,#,#,15,7},
3
/ \
9 20
/ \
15 7
return its bottom-up level order traversal as:
[
[15,7],
[9,20],
[3]
]
思路:按层序遍历得到结果,然后逆序输出就ok了。
class Solution {
public:
vector<vector<int> > levelOrderBottom(TreeNode *root) {
vector<vector<......
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