60、把二叉树打印成多行

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。

==》stack

# -*- 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 []
        res = []
        stack = [pRoot]
        while stack:
            tmp = []
            level = []
            for node in stack:
                tmp.append(node.val)
                if node.left:
                    level.append(node.left)
                if node.right:
                    level.append(node.right)
            stack = level
            res.append(tmp)
        return res

==》queue

# -*- 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 []
        from collections import deque
        q = deque()
        q.append(pRoot)
        res = []
        while q:
            tmp = []
            nextLevel = deque()
            for node in q:
                tmp.append(node.val)
                if node.left:
                    nextLevel.append(node.left)
                if node.right:
                    nextLevel.append(node.right)
            q = nextLevel
            res.append(tmp)
        return res