Given two binary trees, merge them together using the following guidelines:

• For overlapping nodes, sum the weight together as the weight of the new node.
• For non-overlapping nodes, add the not NULL node to the new tree.

The image below shows a sample merge with two binary trees.

Sample Input:

tree1 = [2, 3, 1, 6, 4], tree2 = [7, 5, 9, null, null, 10, 12]

Sample Output:

[9, 8, 10, 6, 4, 10, 12]

数据结构和算法：初级练习题 #34 – 合并二叉树

给定两颗二叉树，把它们按照下面的规则合并在一起：

• 相同位置的节点，把两个节点的重量相加。
• 没有重合的节点，把非空节点加入到新的二叉树中。

上面的图例展示了两颗二叉树合并的结果。

输入样例：

tree1 = [2, 3, 1, 6, 4], tree2 = [7, 5, 9, null, null, 10, 12]

输出样例：

<9, <8, <6, None, None>, <4, None, None>>, <10, <10, None, None>, <12, None, None>>>

Python Solution