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。
说明：本题目包含复杂数据结构TreeNode，点此查看相关信息

  1. # -*- coding:utf-8 -*-
  2. # class TreeNode:
  3. #     def __init__(self, x):
  4. #         self.val = x
  5. #         self.left = None
  6. #         self.right = None
  7. class Solution:
  8.     # 返回二维列表[[1,2],[4,5]]
  9.     def Print(self, pRoot):
  10.         # write code here
  11.         if not pRoot:
  12.             return []
  13.         ret = []
  14.         curr_stack = [pRoot]
  15.         while curr_stack:
  16.             next_stack = []
  17.             curr_val = []
  18.             for node in curr_stack:
  19.                 if node.left:
  20.                     next_stack.append(node.left)
  21.                 if node.right:
  22.                     next_stack.append(node.right)
  23.                 curr_val.append(node.val)
  24.             curr_stack = next_stack
  25.             ret.append(curr_val)
  26.         return ret