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题目

100.相同的树

给你两棵二叉树的根节点 p 和 q ，编写一个函数来检验这两棵树是否相同。

如果两个树在结构上相同，并且节点具有相同的值，则认为它们是相同的。

题解

1. 递归

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution(object):def isSameTree(self, p, q):""":type p: Optional[TreeNode]:type q: Optional[TreeNode]:rtype: bool"""if p is None or q is None:return p is qreturn p.val == q.val and self.isSameTree(p.left, q.left) and self.isSameTree(p.right, q.right)

2. 递归2

# Definition for a binary tree node.
# class TreeNode(object):
#     def __init__(self, val=0, left=None, right=None):
#         self.val = val
#         self.left = left
#         self.right = right
class Solution(object):def isSameTree(self, p, q):""":type p: Optional[TreeNode]:type q: Optional[TreeNode]:rtype: bool"""if not p and not q:return Trueelif not p or not q:return Falseelif p.val != q.val:return Falseelse:return self.isSameTree(p.left, q.left) and self.isSameTree(p.right, q.right)