# Question

Formatted question description: https://leetcode.ca/all/107.html

107	Binary Tree Level Order Traversal II

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]
]

@tag-tree


# Algorithm

The traversal from the bottom sequence is actually traversal from the top, but the final storage method has changed.

Java