Leetcode 116. Populating Next Right Pointers in Each Node

https://leetcode.com/problems/populating-next-right-pointers-in-each-node/

Solution:

# T:O(n) S:O(1)
class Solution:
    # @param root, a tree node
    # @return nothing
    def connect(self, root):
        if root and root.left:
            root.left.next = root.right
            if root.next:
                root.right.next = root.next.left
            self.connect(root.left)
            self.connect(root.right)

Run Time: 120 ms