116. 填充每个节点的下一个右侧节点指针

这里用到的知识点主要是python中collections库中关于队列的使用。

"""
# Definition for a Node.
class Node:
    def __init__(self, val: int = 0, left: 'Node' = None, right: 'Node' = None, next: 'Node' = None):
        self.val = val
        self.left = left
        self.right = right
        self.next = next
"""
import collections


class Solution:
    def connect(self, root: 'Optional[Node]') -> 'Optional[Node]':
        if root is None:
            return root
        Q = collections.deque([root])
        while Q:
            s = len(Q)
            for i in range(s):
                p = Q.popleft()
                if i