617. 合并二叉树

617. 合并二叉树

class Solution {
public:
    TreeNode* mergeTrees(TreeNode* t1, TreeNode* t2) {
        if(t1==NULL)return t2;
        if(t2==NULL) return t1;
        t1->val+=t2->val;
        t1->left=mergeTrees(t1->left,t2->left);
        t1->right=mergeTrees(t1->right,t2->right);
        return t1;
    }
};