70+ Software Development Engineer 3 Interview Questions and Answers

Triggers are database objects that execute automatically in response to certain events. Mutating trigger problem occurs when a trigger tries to read or modify a table that is already being modified by the same transaction.

• Triggers can be used to enforce business rules, audit changes, and maintain referential integrity.

• They can be used to automatically update a table when a related table is updated.

• Mutating trigger problem can be solved by using compound triggers, which allow ...read more

Finding overlapping intervals for calculating final payment of store worker

• Identify all the intervals for which the worker is eligible for payment

• Check for overlapping intervals and merge them

• Calculate the final payment based on the merged intervals

Defining and using a parameterized cursor in PL/SQL

• Declare a cursor variable with parameters

• Open the cursor using the OPEN statement and pass in the parameter values

• Fetch rows from the cursor using the FETCH statement

• Close the cursor using the CLOSE statement

Design a system for companies to schedule events, manage seats, and allow only employees to book shows.

• Create a database to store company information, event schedules, seat availability, and employee details

• Implement an authentication system to verify employee credentials

• Develop a user interface for companies to define event schedules, seat availability, and prices

• Allow employees to search and book shows based on their company affiliation

• Ensure proper validation and error han...read more

Rownum is a pseudocolumn in Oracle that assigns a unique number to each row returned by a query.

• Rownum starts with 1 and increments by 1 for each row returned by the query.

• The expression Rownum > 4 is correct and will return all rows with a Rownum greater than 4.

• Rownum can be used to limit the number of rows returned by a query, for example, 'SELECT * FROM table WHERE Rownum <= 10'.

Flatten a multi-nested object with any key types, including arrays of objects, into a single-level object.

• Use recursion to traverse nested objects and arrays.

• Concatenate keys with a separator (e.g., '.') to form new keys.

• Example: { a: { b: 1 } } becomes { 'a.b': 1 }.

• Handle arrays by iterating through each object and flattening them.

• Example: { a: [{ b: 1 }, { c: 2 }] } becomes { 'a.0.b': 1, 'a.1.c': 2 }.

Query to delete duplicate records from a table

• Use GROUP BY to group the records by the columns that define duplicates

• Use HAVING to filter out groups with count greater than 1

• Use DELETE to remove the duplicate records

An offline store management system is a software that helps manage inventory, sales, and customer data in a physical store without an internet connection.

• The system should have a database to store product information, sales data, and customer information.

• It should have a user-friendly interface for employees to input and access data.

• The system should be able to generate reports on sales, inventory levels, and customer data.

• It should have a backup system in case of data loss o...read more

User defined exceptions can be defined by creating a new class that extends the Exception class.

• Create a new class that extends the Exception class

• Add constructors to the class to initialize the exception

• Throw the exception using the 'throw' keyword

Yes, I have experience with CI/CD, Microservices, Junits, Async APIs, and Multithreading.

• Implemented CI/CD pipelines using Jenkins for automated testing and deployment

• Developed microservices architecture using Spring Boot and Docker containers

• Wrote Junit tests for unit testing and integration testing

• Worked on building async APIs using frameworks like Node.js and Spring WebFlux

• Utilized multithreading in Java applications for improved performance

Design a CRUD of saving and getting a message in Spring boot

• Create a Message entity with fields like id, content, createdDate

• Create a MessageRepository interface extending JpaRepository

• Create a MessageService class with methods for saving, getting, updating, and deleting messages

• Create a MessageController class with endpoints for CRUD operations using @RestController and @RequestMapping annotations

Graph-based approach models flights as nodes and connections, optimizing routes and costs in travel problems.

• Nodes represent airports; edges represent direct flights between them.

• Weighted edges can represent costs, distances, or travel times.

• Algorithms like Dijkstra's or A* can find the shortest path between two airports.

• Example: Finding the cheapest flight from New York to Los Angeles using a graph.

• Graph traversal helps in identifying layovers and multi-leg journeys.

Design a high level design for a subset of Instagram features.

• User authentication and profile creation

• Photo and video uploading with filters

• News feed displaying posts from followed users

• Like, comment, and share functionality

• Direct messaging between users

Find the maximum product of a contiguous subarray in an integer array using dynamic programming.

• Initialize two variables, maxProduct and minProduct, to track the maximum and minimum products up to the current index.

• Iterate through the array, updating maxProduct and minProduct based on the current number and their products.

• If the current number is negative, swap maxProduct and minProduct before updating.

• Keep track of the global maximum product found during the iteration.

• Exampl...read more

Code for Boggle game

• Create a 2D grid of letters

• Generate all possible words using the grid and a dictionary

• Implement a search algorithm to find valid words

• Track score based on word length and rarity

• Allow for multiple players and rounds

Find maximum sum of distinct subarray with length k using sliding window technique.

• Use a sliding window of size k to iterate through the array

• Keep track of the sum of elements within the window

• Maintain a set to keep track of distinct elements in the window

• Slide the window by removing the leftmost element and adding the rightmost element

• Update the maximum sum as you iterate through the array

Design a system for generating report cards with dynamic class/subjects

• Create a database to store student information, class details, and subject details

• Allow users to input class details and subjects for each class dynamically

• Design a template for report cards that can be customized based on class and subjects

• Implement a feature to generate report cards based on the selected class and subjects

• Include options for teachers to input grades and comments for each subject

Design a communication system for chat/notifications

• Use a real-time messaging protocol like WebSocket for chat functionality

• Implement push notifications for notifications to keep users updated

• Include features like read receipts, typing indicators, and message history

• Consider implementing message encryption for security

• Allow users to customize notification settings for different types of messages

The level of a node in a binary tree is determined by the number of edges on the path from the root to that node.

• The level of the root node is 0.

• To find the level of a node, traverse the tree starting from the root and increment a level counter as you move down the tree.

• The level of a node can also be determined by its distance from the root node.

Implemented a real-time collaborative editing feature using WebSockets

• Designed a scalable architecture to handle concurrent edits from multiple users

• Implemented conflict resolution algorithms to ensure data consistency

• Utilized WebSockets for bi-directional communication between clients and server

Equilibrium number refers to a stable state in a system where forces are balanced, often used in algorithms and data structures.

• In data structures, equilibrium can refer to balanced trees like AVL or Red-Black trees.

• Example: In an AVL tree, the balance factor (height difference) of nodes is maintained to ensure O(log n) operations.

• In algorithms, equilibrium can relate to finding stable states in game theory or optimization problems.

• Example: In a Nash equilibrium, no player ca...read more

Design a book reader service similar to Kindle

• Implement a user-friendly interface for browsing and purchasing books

• Include features like bookmarking, highlighting, and note-taking

• Support various file formats such as PDF, EPUB, and MOBI

• Provide options for customization like font size, background color, and reading progress tracking

CNN stands for Convolutional Neural Networks, used for image recognition. YOLO (You Only Look Once) is a real-time object detection model.

• CNNs are deep learning models specifically designed for processing visual data like images and videos.

• They consist of multiple layers such as convolutional, pooling, and fully connected layers to extract features from the input data.

• YOLO is a popular object detection model that divides the image into a grid and predicts bounding boxes and c...read more

Book My Show is a high-level system for booking movie tickets and event tickets online.

• Users can search for movies or events, view showtimes, and book tickets online.

• The system should handle user authentication, payment processing, and ticket confirmation.

• It should also include features like seat selection, seat availability updates, and booking history.

• The system should have a database to store movie/event information, user data, and transaction details.

In-order traversal visits left subtree, current node, then right subtree. Pre-order traversal visits current node, left subtree, then right subtree.

• In-order traversal: left, root, right

• Pre-order traversal: root, left, right

• Example: In-order traversal of tree [1, 2, 3] is [2, 1, 3]

• Example: Pre-order traversal of tree [1, 2, 3] is [1, 2, 3]

Design a service for managing coupons and scratch cards, focusing on user interaction and backend processes.

• User Registration: Users can create accounts to manage their coupons and scratch cards.

• Coupon Creation: Admins can create coupons with attributes like discount percentage, expiration date, and usage limits.

• Scratch Card Generation: Users can receive scratch cards that reveal discounts or prizes when scratched.

• Redemption Process: Users can redeem coupons or scratch card p...read more

Flattening JSON in Node.js involves converting nested objects into a single-level object with dot notation keys.

• Use recursion to traverse nested objects and build a flat structure.

• Example: { a: { b: 1 } } becomes { 'a.b': 1 }.

• Utilize a helper function to manage the current path as you iterate.

• Consider edge cases like arrays and null values.

• Optimize by avoiding unnecessary object copies.