Description
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.
Β
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
Β
Constraints:
- The number of nodes in both trees is in the range
[0, 100]
. -104 <= Node.val <= 104
Solution
Python3
# 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:
def dfs(p, q):
if not p and not q: return True
if not p or not q: return False
return p.val == q.val and dfs(p.left, q.left) and dfs(p.right, q.right)
return dfs(p, q)