Hacker Round Test:
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- Replace a character c1 with c2 and c2 with c1 in a string S. But it was mentioned that the string will be large and needs to be efficient. Brue force solution was giving timed out for most of the test cases.
- Given a string like ‘01001010’, min number of modifications (0 to 1 or 1 to 0) required to make all characters alternative.
- Some math-related questions, which was not clear.
They called for Face-2-Face Interviews to Hyderabad Campus.
Round 1:
- Polymorphism in Java. Write examples for compile and run time polymorphisms
- Difference between list and ArrayList. She was looking for an answer that Arraylist is implemented as a dynamic array unlike the normal list
- String Mutability in Java
- Some questions related to memory allocation in java for objects and arrays.
- Subclass and superclass objects calling each others methods.
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Find Excel column number from column title.
After giving a solution, she asked if this will perform for Large column names like 2**n and all. Then I changed the result variable in my code to Long instead of int .. to handle if its large data. She was expecting more optimization … Then I told, we can go for pattern matching and storing the corresponding value to use them back. She asked which data structure I would use. I told I would use trie.
Round 2: It was a design-oriented round.
- Write Singleton Pattern using lazy implementation. Then asked to make it thread-safe and improve it further.
- Few questions about exposing rest resources and about authentication.
- Data Structures and design patterns used in the present company.
- If you want to send mail each time an exception occurs in code how will you do it?
- Write the basic try-catch implementation
- Implement the java method which creates a table and a few more steps. How will you handle if an exception occurs during the other steps after table creation?
- Class A has a Class B in it. Class B has class A in it. It’s a cyclic dependency, how will your present framework handle this?
- Is serializable used in our code
Round 3:
- About the current company and team
- Reverse a Linked List in groups of given size
- Asked questions about databases as query optimization was bit highlighted in my resume.
- Different types of indexes and how they work and implementation etc
- Differences between b tree and b+ tree
- What are joins and how they work