把二叉树打印成多行

题目描述

从上到下按层打印二叉树，同一层结点从左至右输出。每一层输出一行。

思路:

层次遍历，利用列表进行辅助

# -*- coding:utf-8 -*-
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
class Solution:
    # 返回二维列表[[1,2],[4,5]]
    def Print(self, pRoot):
        # write code here
        if not pRoot:
            return []
        p = []
        p.append(pRoot)
        result = []
        while p:
            temp = []
            x = []
            for i in p:
                temp.append(i.val)
                if i.left:
                    x.append(i.left)
                if i.right:
                    x.append(i.right)
            p = x
            result.append(temp)
        return result