给定一棵二叉树,返回齐自底向上的层序遍历。
数据范围:二叉树上节点数满足
,二叉树上的值满足 
样例图:
# class TreeNode: # def __init__(self, x): # self.val = x # self.left = None # self.right = None # # 代码中的类名、方法名、参数名已经指定,请勿修改,直接返回方法规定的值即可 # # # @param root TreeNode类 # @return int整型二维数组 # class Solution: def levelOrderBottom(self , root: TreeNode) -> List[List[int]]: # write code here res = [] q = [] q.append(root) while len(q) != 0: next_q = [] tmp = [] for node in q: tmp.append(node.val) if node.left is not None: next_q.append(node.left) if node.right is not None: next_q.append(node.right) res.append(tmp) q = next_q return res[::-1]