Delhivery Interview Experience | Set 4 (Off-Campus)

There were 4 rounds in total . 3 Technical + 1 HR . Every round is elimination round

Round 1: 

He asked my 2 algorithmic problems.

1. Find the number of anagram pairs in a string . For example for string “abba”, there are 4 such pairs {a, a}, {b, b}, {ab, ba} , {abb, bba} .
2. A string contains only G, T, C, A . Length of the string is always divisible by 4 . A stable string is a string which contains equal number of G, T , C, and A . Given a string containing only G, T, C, A find the length of the smallest possible substring that he can replace to make  it a stable  string? For Example in string GAAATAAA . optimal solution is to replace AAATA  with  TTCCG resulting in GTTCCGAA.
3. Design a system for shortening  URL application.

Round 2:

1. Discussion on previous projects
2. Differences between C++, Java and Python
3. Why Python is slower than Java.
4. Do you really need API Versioning?
5. Design a database for Warehouses for the Delhivery team .
6. Discussion on Singleton patter, factory pattern, Builder pattern, abstract factory pattern and the implementation of all in any language  . I did it in java.
7. Normalisation in RDBMS
8. There is a network failure  in a distributed database . Discuss the scenario in all three possible cases using CAP theorem.
9. Reverse Level order traversal in a Binary Tree . I did it using Queue DS and then He asked me to do minimal changes in the code to make it inOrder Traversal ( Use Stack instead of Queue ).
10. Static binding vs Late Binding in C++ .

Round 3:

It was the director’s round

1. 2 Engineering problems that you have solved.
2. There are N vehicles in Delhivery and 1 vehicle can do atmost (2 drops or 2 pick ups or 1 pickup + 1 drop) per hour . Client books his order between start time and end time for the next day . I need to return true or false . True if I can book a vehicle for that period else False.
3. Design a database for an organisation such that it has employees, every employee can have a role. One role can have many permissions for example  Rola – Manager can code, can manage, can recruit . Role – Coder can code but not manage, Role – HR can manage and recruit. All tables should be in BCNF.
4. Using this database, create a query such that it returns all the employee name who can not code.

Round 4:

1. Tell me about yourself .
2. Previous Experience
3. What are your aspirations in life.
4. What are your strengths and weaknesses?
5. What are your career options right now?