Oracle

Role: Software Engineer

College: Tier-3 College, 2022 passout

Interview Date: April 2024

Interview Type: Full-Time (F2F hiring drive)

Result: Offer

Difficulty: Medium

Rounds: 3 rounds

Topics Asked: Data Structures and Algorithms (LC Medium, Rotate array k to the left, Insert/delete/getRandom in O(1), Copy linked list with a random pointer, Delete given node from linked list, Mirror image of a binary tree, Detect cycle in a linked list, Find the node that has a cycle in a linked list, Snake and ladder, Shortest unique prefix for every word in an array, Longest substring without repeating characters, Height of a binary tree), System Design (past project design, CI/CD), SQL Queries (nth highest salary, joins, subqueries, IN, EXISTS, ANY, indexes), Java, REST APIs, Concurrency, Load/Performance testing, Locking, Deadlock

Experience:

This candidate received an offer for a Software Engineer role at Oracle in April 2024 through a face-to-face hiring drive.

Online Test (HackerRank). The online assessment included 2 coding questions, which were LeetCode Medium level, and 20 MCQs.

Onsite Round 1. This round involved a panel of two members and lasted over 1.5 hours. Questions delved into the design of past projects and the features worked on, as well as explaining the CI/CD of the current project. Several SQL queries were asked, including: "Find the nth highest salary of employee," "Given a scenario write the query using both joins and sub queries," "Difference between IN, EXISTS, ANY," and questions on the usage and necessity of indexes. Data Structures and Algorithms questions included "Longest substring without repeating characters" and "Height of a binary tree". There were also questions on batch processing, Java, REST APIs, how to handle concurrency, and experience with load or performance testing.

Onsite Round 2. This round included implementing a recursive function that can print 1,2,3,4,5.... and ....,5,4,3,2,1. A math puzzle was also presented. Questions revolved around locking mechanisms and identifying operations that could lead to a deadlock situation in a given scenario. The interviewer also asked questions about the candidate's past experience.

Additional Coding Questions (from the same experience, likely across technical rounds): "Rotate array k to the left" (optimized from O(n^2) to O(n) without extra space by reversing), "Insert, delete, and getRandom in O(1)" (solved using knowledge from LeetCode), "Copy linked list with a random pointer" (attempted with map, interviewer asked for solution without extra space, which the candidate couldn't optimize), "Delete given node from the linked list (Head of the linked list is not given)" (optimized from O(n) to O(1) after some time), "Mirror image of a binary tree" (solved using recursion), "Detect cycle in a linked list" (solved with slow and fast pointer), "Find the node that has a cycle in a linked list" (follow-up, solved with hints), "Snake and ladder" (pseudo-code and explanation of data structures/logic), "Find the shortest unique prefix for every word in an array" (solved using tries).

The candidate was a little confused about the result as the second and third rounds were not up to the mark, but received a call from the recruiter HR after two days confirming selection, and the offer was extended after 15 days.