# -*- coding:utf-8 -*-

class TreeLinkNode:

def __init__(self, x):

self.val = x

self.left = None

self.right = None

self.next = None

class Solution:

def GetNext(self, pNode):

# write code here

pnext = None

if pNode is None:

return pnext

if pNode.right is not None:

nextnode = pNode.right

while nextnode and nextnode.left:

nextnode = nextnode.left

pnext = nextnode

elif pNode.next:

pcur = pNode

pparent = pNode.next

while pparent and pparent.left!=pcur:

pcur = pparent

pparent = pcur.next

pnext = pparent

return pnext