思路
先序遍历合并
代码
class Solution {
public:TreeNode* mergeTrees(TreeNode* root1, TreeNode* root2) {if(root1 != nullptr && root2 != nullptr){root1->val += root2->val;root1->left = mergeTrees(root1->left, root2->left);root1->right = mergeTrees(root1->right, root2->right);}else if(root1 == nullptr && root2 != nullptr){root1 = root2;}else if(root1 != nullptr && root2 == nullptr){return root1;}return root1;}
};