剑指offer57-二叉树的下一个结点

# -*- 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
        if not pNode:
            return None
        tmp=pNode
        while tmp.next:                                #找到树的根节点
            tmp=tmp.next
        a=[]
        self.in_search(tmp,a)
        #if a.index(pNode)+1<=len(a)-1:
        #    return a[a.index(pNode)+1]
        #return None
        try:
            return a[a.index(pNode)+1]
        except:
            return None

    def in_search(self,tree,a):                  #注意这里有递归，所以不要在函数里定义a=[]
        if not tree:
            return None
        self.in_search(tree.left,a)
        a.append(tree)
        self.in_search(tree.right,a)