我的算法之路27--树的子结构

# -*- coding:utf-8 -*-
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None
class Solution:
    def HasSubtree(self, pRoot1, pRoot2):
        # write code here
        result=False
        if not pRoot1 or not pRoot2:
            return False
        if pRoot1.val==pRoot2.val:
            result=self.issub(pRoot1.left,pRoot2.left) and self.issub(pRoot1.right,pRoot2.right)
        if not result:
            return self.HasSubtree(pRoot1.left,pRoot2) or self.HasSubtree(pRoot1.right,pRoot2)
        return result
    def issub(self,pRoot1,pRoot2):
        if not pRoot2:
            return True
        if not pRoot1:
            return False
        if pRoot1.val !=pRoot2.val:
            return False
        return self.issub(pRoot1.left,pRoot2.left) and self.issub(pRoot1.right,pRoot2.right)