Method deepcopy

95. Unique Binary Search Trees II/Solution.cpp:55–61

    }
    
    TreeNode * deepcopy(TreeNode * root) {
        if (root == NULL) return NULL;
        TreeNode * p = new TreeNode(root->val);
        p->left = deepcopy(root->left);
        p->right = deepcopy(root->right);
        return p;
    }
};

int main() {