CODE

# 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:
        q = deque()
        q.append(root)
        while q:
            node = q.popleft()
            if node.val == subRoot.val:
                if self.isSametree(node, subRoot):
                    return True
            if node.left: q.append(node.left)
            if node.right: q.append(node.right)
        return False
    
    def isSametree(self, p: Optional[TreeNode], q: Optional[TreeNode]) -> bool:
        if not p and not q:
            return True
        if p and q and p.val == q.val:
            return self.isSametree(p.left, q.left) and self.isSametree(p.right, q.right)
        return False