题目
判断b是不是a的子树
思路
先判断根节点是否一样,若一样则递归判断左右子树,若不一样就用b的根节点去比较a的左右子树。
代码
# -*- 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):
result = False
if pRoot2 is None or pRoot1 is None:
return False
if pRoot1.val == pRoot2.val:
result = self.issubtree(pRoot1,pRoot2)
if result is False:
return self.HasSubtree(pRoot1.left,pRoot2) or self.HasSubtree(pRoot1.right,pRoot2)
return result
def issubtree(self,node1,node2):
if node2 is None:
return True
if node1 is None:
return False
if node1.val != node2.val:
return False
else:
return self.issubtree(node1.left, node2.left) and self.issubtree(node1.right, node2.right)