617_merg_two_binary_trees.py

# Definition for a binary tree node.
# class TreeNode:
#     def __init__(self, x):
#         self.val = x
#         self.left = None
#         self.right = None

class Solution:
    def mergeTrees(self, t1: TreeNode, t2: TreeNode) -> TreeNode:
        if not t1 and not t2: return None
        ans = TreeNode((t1.val if t1 else 0) + (t2.val if t2 else 0))
        ans.left = self.mergeTrees(t1 and t1.left,t2 and t2.left )
        ans.right = self.mergeTrees(t1 and t1.right,t2 and t2.right)
        return ans