Park+

Role: SDE1

College: Not Specified

Interview Date: May 18, 2024 (Round 1), May 20, 2024 (Round 2), May 23, 2024 (Round 3)

Interview Type: Off-Campus (Applied through Google Doc shared on LinkedIn)

Result: Not Specified (Implied progression through rounds)

Difficulty: Medium

Rounds: 3 rounds

Topics Asked: Project Architecture, OOP (Multiple/Multilevel Inheritance, Function Overloading/Overriding, Exception Handling), DBMS (Primary/Composite Key, Joins, SQL queries), DSA (Decode String, Largest BST in Binary Tree, String partition problem, Sorted array merge), System Design (Parking Management System), OS (Deadlock, Starvation, Paging, Round Robin, FIFO), Computer Networks (HTTP vs HTTPS, URL working, Socket), Puzzle

Experience:

The candidate, with 2 years of experience, applied for an SDE2 role but was suggested for SDE1. The tech stack mentioned in the resume was Java, Spring, and DBMS.

Round 1 (JobTwine - 50 minutes): This was with a third-party hiring agency. Questions included: Explain architecture of your current project. Explain multiple and multilevel inheritance. Explain function overloading and overriding, with output of example codes. What is primary and composite key? Explain different types of joins. How is Exception handling done? Can we create our own exception? DSA question: LeetCode - Decode String. Why do we write unit test cases?

Round 2 (1 hour): This round had 2 DSA questions and 1 SQL query, along with CS fundamentals.

DSA Questions:

1. Given a string, find the number of parts such that no two parts have common characters. Input: `ababcbacadefegdehijhklij`, Output: `3` (`ababcbaca`, `defegde`, `hijhklij`).
2. Given a binary tree, find the size of the largest BST in it.

SQL Query: Find the department and department-wise total salary, and display it in ascending order of salary.

CS Fundamentals: HTTP vs HTTPS, what happens when you type a URL, Mutex and Semaphore, Indexing and types of indexing.

Round 3 (1 hour - with DOE): This round included: Introduction. Explanation of tech stacks and Park+ products. A screen-shared test with 2 SQL queries (update and select using union, 7 minutes each). System Design: Design a parking management system for malls and buildings. What is stateful and stateless?

Final Round (DOE): This round included: Introduction. One SQL query: Given an Employee table (ID, Name, Salary, Department, ManagerID, DOB), find the employee with the max salary in each department. One coding question: Given 2 sorted arrays of integers, sort them in place so that the first array has the first n smallest elements and the second array has the remaining elements. (Example: Arr1 = [1, 3, 5, 7, N], Arr2 = [2, 4, 6, 8, 9, M] -> Output Arr1:, Arr2:). Questions on OS: What is deadlock? What is starvation? Paging and page miss. Round robin, FIFO. Computer Networks: What is socket? Normalization and its types. One puzzle: A horse carrying mangoes problem (3000 mangoes, 1000 km, 1000 mangoes/trip, 1 mango/km, only one horse - maximize mangoes to destination).