面试题 04.03. 特定深度节点链表

给定一棵二叉树，设计一个算法，创建含有某一深度上所有节点的链表（比如，若一棵树的深度为 D，则会创建出 D 个链表）。返回一个包含所有深度的链表的数组。

示例：

输入：[1,2,3,4,5,null,7,8]

输出：[[1],[2,3],[4,5,7],[8]]

Python 解答：

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

# Definition for singly-linked list.
# class ListNode:
#     def __init__(self, x):
#         self.val = x
#         self.next = None

class Solution:
    def listOfDepth(self, tree: TreeNode) -> List[ListNode]:
        lis = []
        if not tree:
            return []
        queue = [tree]
        while queue:
            root = ListNode(0)
            p = root
            temp = []
            for node in queue:
                new = ListNode(node.val)
                p.next = new
                p = new
                if node.left:
                    temp.append(node.left)
                if node.right:
                    temp.append(node.right)
            lis.append(root.next)
            queue = temp
        return lis