标签：else 注意 rsa erb pre python 12px style 思路
问题描述：
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,null,null,15,7],
3
/ 9 20
/ 15 7
return its bottom-up level order traversal as:
[ [15,7], [9,20], [3] ]
注意是每一层的所有数字放入同一个list内
思路：二叉树问题，考虑使用递归算法，计算出每一层的所有元素值
# Definition for a binary tree node. # class TreeNode: # def __init__(self, x): # self.val = x # self.left = None # self.right = None class Solution: def levelOrderBottom(self, root: TreeNode) -> List[List[int]]: if root == None: return [] def order(rootx,level): if rootx == None:return if (level) == len(result): result.append([rootx.val]) else: result[level].append(rootx.val) order(rootx.left,level+1) order(rootx.right,level+1) result = [] order(root,0) return result[::-1]
Python3解leetcode Same TreeBinary Tree Level Order Traversal II
标签：else 注意 rsa erb pre python 12px style 思路
原文地址：https://www.cnblogs.com/xiaohua92/p/11072788.html
