填充每个节点的下一个右侧节点指针-二叉树116-python

算法思想：

python

# 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':
        if not root:
            return 
        self.connectTwoNode(root.left, root.right)

        return root

    def connectTwoNode(self, node1, node2):
        if not node1 or not node2:
            return 

        node1.next = node2
        self.connectTwoNode(node1.left, node1.right)
        self.connectTwoNode(node2.left, node2.right)
        self.connectTwoNode(node1.right, node2.left)