題目描述

輸入兩棵二叉樹A，B，判斷B是不是A的子結構。（ps：我們約定空樹不是任意一個樹的子結構）

時間限制：1秒；空間限制：32768K

解題思路

解題思路分為兩步，主要用到了遞迴的方法。第一步先遍歷樹A，找到和樹B根節點值相同的節點A'；第二步判斷以A'為根節點的子樹中是否包含樹B。

# -*- 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 pRoot1!=None and pRoot2!=None:
            if pRoot1.val == pRoot2.val:
                result = self.iscomprise(pRoot1,pRoot2) #不寫self.會報錯
            if result != True:
                result = self.HasSubtree(pRoot1.left,pRoot2)
            if result != True:
                result = self.HasSubtree(pRoot1.right,pRoot2)
        return result
    
    def iscomprise(self, pRoot1, pRoot2):
        if pRoot2 == None:
            return True
        if pRoot1 == None:
            return False
        if pRoot1.val == pRoot2.val:
            return self.iscomprise(pRoot1.left, pRoot2.left) and self.iscomprise(pRoot1.right, pRoot2.right)