python-leetcode面试题解之第102题二叉树的层序遍历-题解.zip

# Definition for a binary tree node. # class TreeNode(object): # def __init__(self, x): # self.val = x # self.left = None # self.right = None class Solution(object): # def levelOrder(self, root): # """ # :type root: TreeNode # :rtype: List[List[int]] # """ # res = [] # if root is None: # return [] # self.get_level(res, root, 0) # return res # # def get_level(self, res, root, depth): # if root is None: # return # if depth == len(res): # res.append([]) # res[depth].append(root.val) # self.get_level(res, root.left, depth + 1) # self.get_level(res, root.right, depth + 1) def levelOrder(self, root): # https://leetcode.com/discuss/90680/9-lines-python-code if root is None: return [] q = [[root]] for level in q: record = [] for node in level: if node.left: record.append(node.left) if node.right: record.append(node.right) if record: q.append(record) return [[x.val for x in level] for level in q]