Backend Developer

Level Order Traversal can be used here. 
Algorithm :
1. Maintain a hash map for the branch of each node.
2. Traverse the tree in level order fashion.
3. In level order traversal, maintain a queue which holds, node and its vertical branch.
* pop from queue.
* add this node's data in vector corresponding to its branch in the hash.
* if this node hash left child, insert in the queue, left with branch - 1.
* if this node hash right child, insert in the queue, right with branch + 1.

Time Complexity of the above implementation is O(n Log n).

Java is purely an object oriented language due to the absence of global scope, Everything in java is an object, all the program codes and data resides within classes and objects. It comes with an extensive set of classes, arranged in packages, object model in java in sample and easy to extend.

Indexing is used to optimize the performance of a database by minimizing the number of disk accesses required when a query is processed. The index is a type of data structure. It is used to locate and access the data in a database table quickly.
Index structure:
Indexes can be created using some database columns.
The first column of the database is the search key that contains a copy of the primary key or candidate key of the table. The values of the primary key are stored in sorted order so that the corresponding data can be accessed easily.
The second column of the database is the data reference. It contains a set of pointers holding the address of the disk block where the value of the particular key can be found.

Partitioning is the database process where very large tables are divided into multiple smaller parts. By splitting a large table into smaller, individual tables, queries that access only a fraction of the data can run faster because there is less data to scan. The main of goal of partitioning is to aid in maintenance of large tables and to reduce the overall response time to read and load data for particular SQL operations.

Tip 1 : Firstly, remember that the system design round is extremely open-ended and there’s no such thing as a standard answer. Even for the same question, you’ll have a totally different discussion with different interviewers.

Tip 2 : Before you jump into the solution always clarify all the assumptions you’re making at the beginning of the interview. Ask questions to identify the scope of the system. This will clear the initial doubt, and you will get to know what are the specific detail interviewer wants to consider in this service.

Tip 3 : Design your structure and functions according to the requirements and try to convey your thoughts properly to the interviewer so that you do not mess up while implementing the idea .