题目描述

blablabla

样例

blablabla

算法1

() $O(n^2)$

blablabla

时间复杂度分析：blablabla

Python 代码

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution(object):
    def hasSubtree(self, pRoot1, pRoot2):
        """
        :type pRoot1: TreeNode
        :type pRoot2: TreeNode
        :rtype: bool
        """
        if not pRoot1 or not pRoot2:
            return False
        if self.isSame(pRoot1, pRoot2):
            return True
        return self.hasSubtree(pRoot1.left, pRoot2) or self.hasSubtree(pRoot1.right, pRoot2)

    def isSame(self, r1, r2):
        if not r2: # 出口很重要
            return True 
        if not r1 or r1.val != r2.val:
            return False
        return self.isSame(r1.right, r2.right) and self.isSame(r1.left, r2.left)