题解 | #求二叉树的层序遍历#

# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

#
# 
# @param root TreeNode类 
# @return int整型二维数组
#
class Solution:
    def levelOrder(self , root ):
        def do(root ,level):
            if root == None:
                return
            else:
                if len(self.treelist) < level:
                    self.treelist.append([])
                self.treelist[level-1].append(root.val)
                if root.left != None:
                    do(root.left, level+1)
                if root.right != None:
                    do(root.right, level+1)
        # write code here
        self.treelist = []
        do(root,1)
        return self.treelist