21-2-25

Two rounds were conducted virtually, one after the other. HackerRank's coding platform was used to test skills live. The interview revolved around SQL and DSA.

Software Engineer

1st round:

• SQL: There is a student table with student ID and other parameters. Get alternative IDs as output.
• SQL: There is an Orders table, which has customer_id, order_id, and etc. Get the customer_id who placed the maximum orders. If there's a tie, get the lexicographically smallest customer_id.
• Problem: https://leetcode.com/problems/minimum-add-to-make-parentheses-valid/description/ - Same problem, but the bracket '(' can be added to ')' to make it valid, not vice versa. If not possible, return -1.
• Problem: Longest Common Subsequence problem.
• Concept: Didn't ask to code for this question, just the logic. https://leetcode.com/problems/course-schedule/description/

2nd round:

• SQL: Indexes and types of indexes, stored procedures, disadvantage of having too many non-clustered indexes.
• SQL: If a table has many unnecessary columns that are not used for retrieval (like for indexing) but should be present in the DB, how would you change the format?
• DB Design: Gave a scenario of data and asked to design tables and relations. A student has multiple phone numbers and can take multiple subjects.
• SQL: Asked to get the phone numbers of the student who took the subject 'Maths'.
• Object-Oriented Design: Asked to create classes and their objects for a scenario: Directory. Each directory has folders, and each folder has files. A folder object is passed to a function to print all files and subsequent files.