Old Wei wins the offer to take you to learn --- Brush title series (17 sub-tree structure)

17. substructure tree

problem:

Two binary inputs A, B, B is judged not substructure A's. (Ps: we agreed empty tree is not a tree any substructure)

solve:

thought:

We just need to find out whether there is a value equal to a node and b-node, and then recursively view the left and right nodes are equal to

python code:

# -*- 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
        if pRoot1==None or pRoot2==None:
            return False
        return self.istree(pRoot1,pRoot2) or self.HasSubtree(pRoot1.left,pRoot2) or self.HasSubtree(pRoot1.right,pRoot2)
        
    def istree(self,p1,p2):
        if p2==None:
            return True
        if(p1==None or p1.val!=p2.val):
            return False
        return self.istree(p1.left,p2.left) and self.istree(p1.right,p2.right)