題目 : 100. Same Tree
Given the roots of two binary trees p
and q
, write a function to check if they are the same or not.
Two binary trees are considered the same if they are structurally identical, and the nodes have the same value.
Example 1:
Input: p = [1,2,3], q = [1,2,3]
Output: true
Example 2:
Input: p = [1,2], q = [1,null,2]
Output: false
Example 3:
Input: p = [1,2,1], q = [1,1,2]
Output: false
1.
# Definition for a binary tree node.
# class TreeNode:
# def __init__(self, val=0, left=None, right=None):
# self.val = val
# self.left = left
# self.right = right
class Solution:
def isSameTree(self, p: Optional[TreeNode], q: Optional[TreeNode]) -> bool:
# 如果p和q的node都是None,代表比對完成
if p == None and q == None:
return True
# 如果p和q的node如果有一個是None,代表其中一個已經沒有node可以比對
# p和q不相等,回傳False
if p== None or q == None:
return False
# 比對p和q的node值 比對左子樹 比對右子樹
# 如果3個都是True,代表p和q是相同的tree
return (p.val == q.val) and self.isSameTree(p.left, q.left) and self.isSameTree(p.right, q.right)