117. Populating Next Right Pointers in Each Node II刷题笔记

参考的这个题解，其中注意python的变量是标签，给tail赋next的时候可能会影响到node
https://leetcode.com/problems/populating-next-right-pointers-in-each-node-ii/discuss/37824/AC-Python-O(1)-space-solution-12-lines-and-easy-to-understand

"""
# 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
"""

class Solution:
    def connect(self, root: 'Node') -> 'Node':
        tail = dummy = Node(0)
        node = root
        while node:
            tail.next = node.left
            if tail.next:
                tail = tail.next
            tail.next = node.right
            if tail.next:
                tail = tail.next
            node = node.next
            if not node:
                tail = dummy
                node = dummy.next            
                
        return root