2025-07-30 14:54:50 +0000 UTC

# 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 isSubtree(self, root: Optional[TreeNode], subRoot: Optional[TreeNode]) -> bool:
        def dfs(node: Optional[TreeNode], sub_node: Optional[TreeNode]) -> bool:
            if not node and not sub_node:
                return True
            if not node or not sub_node:
                return False
            if node.val != sub_node.val:
                return False
            return dfs(node.left, sub_node.left) and dfs(node.right, sub_node.right)
        
        def dfs2(node: Optional[TreeNode], sub_node: Optional[TreeNode]) -> bool:
            if dfs(node, sub_node):
                return True
            if not node or not sub_node:
                return False
            return dfs2(node.left, sub_node) or dfs2(node.right, sub_node)

        return dfs2(root, subRoot)