LC100. Same Tree

# 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 p is None and q is None:
                return True
            elif p is None or q is None:
                return False
 
            if p.val != q.val:
                return False
            
            if not dfs(p.left, q.left) or not dfs(p.right, q.right):
                return False
            
            return True
        
        return dfs(p, q)

Complexity

Time: $O(n)$
Space: $O(n)$