from typing import Optional

# https://leetcode.com/problems/flip-equivalent-binary-trees
class TreeNode:
    def __init__(self, val=0, left=None, right=None):
        self.val = val
        self.left = left
        self.right = right

class Solution:
    def flipEquiv(self, root1: Optional[TreeNode], root2: Optional[TreeNode]) -> bool:
        if root1 == None and root2 == None:
            return True
        if root1 == None or root2 == None:
            return False
        if root1.val != root2.val:
            return False
        flip = False
        if (
                (root1.left == None and root2.right == None) or \
                (root1.left != None and root2.right != None and \
                root1.left.val == root2.right.val)
            ) and \
            (
                (root1.right == None and root2.left == None) or \
                (root1.right != None and root2.left != None and \
                    root1.right.val == root2.left.val)
            ):
            flip = True
        if flip:
            tmp = root2.left
            root2.left = root2.right
            root2.right = tmp
        return self.flipEquiv(root1.left, root2.left) and \
            self.flipEquiv(root1.right, root2.right)