new_contents: # -*- coding:utf-8 -*-
  # Definition for a  binary tree node
  # class TreeNode:
  #     def __init__(self, x):
  #         self.val = x
  #         self.left = None
  #         self.right = None
  
  
  class Solution:
      # @param p, a tree node
      # @param q, a tree node
      # @return a boolean
      def isSameTree(self, p, q):
          if p is None or q is None:
              return p == q
          if p.val != q.val:
              return False
          if not self.isSameTree(p.left, q.left):
              return False
          if not self.isSameTree(p.right, q.right):
              return False
          return True
  
subject: add leetcode Same Tree