Merge two Binary Search Trees (BST)

|     Approaches           | Time Complexity  | Space Complexity |
+==================+=================+===========================+
| Inorder Approach         |O(n+m)              | O(n+m)           |
+------------------+--------------------+------------------------+
| Stack Based Approach     | O(n+m)             | O(max(m,n))    |
+------------------+--------------------+------------------------+