200+ Software Development Engineer II Interview Questions and Answers

Calculate sum of large numeric comma separated strings without converting to integers.

• Split the strings by comma to get individual numbers

• Iterate from right to left and add digits, carrying over if necessary

• Maintain correct position of commas in the output string

Design a bus booking system with user management, route selection, and seat booking features.

• User authentication: Implement login/signup using email and password.

• Route selection: Allow users to choose from multiple operational routes based on their travel needs.

• Bus listing: Display all buses available on the selected route with details like departure time and bus type.

• Seat booking: Enable users to select and book available seats on the bus.

• Booking history: Provide users with ...read more

Design a file system similar to Google Drive with features for uploading, sharing, and version control.

• File Uploading: Users can upload files of various formats (e.g., .docx, .pdf) with a progress indicator.

• File Downloading: Users can download files with options for different formats or versions.

• File Sharing: Users can share files with specific users or generate shareable links with permissions.

• Data Loss Handling: Implement redundancy and backups using distributed storage sys...read more

Given an array, find a subset that sums to a given sum K and print all triplets that sum to K.

• Use a recursive approach to find subsets that sum to K

• Use a nested loop to find triplets that sum to K

• Avoid using duplicate elements in triplets

Design a portfolio management system to add and sell stocks, calculate returns, and display current prices and returns.

• Create a class for the portfolio with methods to add and sell stocks

• Implement a method to calculate the percentage return on the portfolio

• Maintain a list of stocks in the portfolio with their current prices and returns

• Use arrays or lists to store the portfolio data

• Ensure proper error handling for invalid inputs or insufficient data

Truncate removes all rows from a table, while delete removes specific rows. Truncate is faster but cannot be rolled back.

• Truncate is a DDL operation while delete is a DML operation

• Truncate resets the identity seed of the table, delete does not

• Truncate is faster as it does not log individual row deletions, delete logs each row deletion

• Truncate cannot be used on tables referenced by a foreign key constraint, delete can be used

• Truncate operation cannot be rolled back, delete ope...read more

Design a system for onboarding financial instruments with user-defined limits for transactions and daily amounts.

• Onboarding Process: Define a user interface for inputting financial instrument details, such as name, type, daily limit, and transaction count.

• Validation: Implement validation checks to ensure limits are within acceptable ranges (e.g., daily amount must be > 0).

• Storage: Store the financial instrument details in a database, ensuring proper indexing for quick retriev...read more

Find a missing number in an unsorted array with elements in the range [1,n].

• Use a hash set to store the elements and check for missing numbers.

• Calculate the sum of all elements and subtract it from the sum of the range [1,n].

• Use XOR operation to find the missing number.

Merge Sort implementation for a 2D array with varying row lengths.

• Iterate through each row and apply Merge Sort individually.

• Merge the sorted rows together using a modified merge function.

• Handle cases where rows have different lengths by adjusting merge logic.

Design a hierarchical database structure for categories and subcategories similar to Flipkart's menu list.

• Use a self-referential table for categories.

• Each category can have a parent category ID to establish hierarchy.

• Example: 'Electronics' can have subcategories like 'Mobiles', 'Laptops'.

• Subcategories can further have their own subcategories, e.g., 'Mobiles' can have 'Smartphones', 'Feature Phones'.

• Consider adding attributes like 'category_name', 'parent_id', and 'category_le...read more

Calculate top 20 percentile of student details based on score in a student table.

• Calculate the 80th percentile score using formula: 80th_percentile = 0.8 * total_students

• Sort the scores in descending order and find the score at 80th percentile position

• Retrieve student details with scores greater than or equal to the 80th percentile score

Use channels in Go to sync two goroutines passing data between them.

• Create a channel to pass data between the goroutines

• Use a select statement to wait for data to be passed

• Ensure proper synchronization to avoid race conditions

Design a database structure for an e-commerce service to showcase ordered products.

• Create a 'products' table with columns like product_id, name, price, etc.

• Create an 'orders' table with columns like order_id, customer_id, order_date, etc.

• Create a 'order_details' table to link products with orders, with columns like order_id, product_id, quantity, etc.

• Use foreign keys to establish relationships between tables.

• Consider indexing columns for faster retrieval of data.

To handle concurrent editing in Google Sheets, use operational transformation to synchronize changes and resolve conflicts.

• Implement operational transformation to track and merge concurrent edits

• Use version control to manage different versions of the sheet

• Apply locking mechanisms to prevent conflicts during editing

• Utilize real-time collaboration features to notify users of changes

• Implement conflict resolution strategies, such as last writer wins or manual resolution

Key considerations for e-commerce design include secure authentication, efficient inventory management, and user experience.

• Implement strong authentication methods (e.g., OAuth, two-factor authentication) to protect user accounts.

• Use SSL certificates to encrypt data during transmission, ensuring secure transactions.

• Design a user-friendly interface for easy navigation and product discovery.

• Integrate real-time inventory management systems to track stock levels and avoid oversel...read more

Design a Stack Overflow-like application for Q&A with user interactions and content management.

• User Authentication: Users can register, log in, and manage profiles.

• Question and Answer Posting: Users can post questions and answers, with support for markdown formatting.

• Voting System: Implement upvote and downvote features for questions and answers.

• Tags and Categories: Allow users to tag questions for better organization and searchability.

• Search Functionality: Enable users to se...read more

To find the minimum steps from x to y, use operations of subtracting 1 or multiplying by 2 strategically.

• If x >= y: The only option is to subtract 1, so steps = x - y.

• If x < y: Use a combination of operations. For example, if x = 3 and y = 10, multiply by 2 to get 6, then subtract to reach 10.

• Working backwards can simplify the problem: If y is even, divide by 2; if odd, add 1 to make it even, then divide.

• Example: To go from 5 to 20, multiply 5 by 2 to get 10, then multiply by...read more

A hashmap is a data structure that stores key-value pairs and allows for constant time lookup and insertion.

• Hashmaps use a hash function to map keys to indices in an array.

• Collisions can occur when multiple keys hash to the same index, which can be resolved using techniques like chaining or open addressing.

• Example: HashMap<String, Integer> map = new HashMap<>(); map.put("key", 123); int value = map.get("key");

Create a console application to show flights between two cities in min no of hops

• Use graph traversal algorithms like BFS to find the shortest path between two cities

• Represent cities and flights as nodes and edges in a graph data structure

• Implement a console interface for users to input two cities and display the shortest path between them

To build a responsive Web UI page with large images, use lazy loading, image optimization, and responsive design techniques.

• Implement lazy loading to only load images when they are in the viewport.

• Optimize images for web by compressing them and using modern image formats like WebP.

• Use responsive design techniques like CSS media queries to adjust image sizes based on screen resolution.

• Consider implementing a content delivery network (CDN) to serve images faster.

• Use placeholder...read more

Convert a string representation of an integer to its integer value, handling edge cases and invalid inputs.

• Use the built-in function int() in Python: e.g., int('123') returns 123.

• Handle leading/trailing spaces: e.g., int(' 42 ') returns 42.

• Manage invalid inputs: e.g., int('abc') raises a ValueError.

• Consider negative numbers: e.g., int('-42') returns -42.

• Handle large numbers: e.g., int('12345678901234567890') returns 12345678901234567890.

The system had over 1 million users worldwide.

• The system had a global user base.

• The user count exceeded 1 million.

• Users were from various countries and regions.

Implement a simplified Video Codex using data structures

• Use a hash table to store key-value pairs of video frames and their corresponding codecs

• Implement a priority queue to efficiently retrieve the most frequently accessed video frames

• Consider using a linked list to maintain the order of video frames in the codex

Efficiently generating unique random numbers can be achieved using algorithms and data structures that ensure no repetitions occur.

• Use a Set: Store generated numbers in a Set to automatically handle duplicates. Example: `Set<Integer> uniqueNumbers = new HashSet<>();`

• Shuffle an Array: Create an array of numbers and shuffle it. Example: `Collections.shuffle(Arrays.asList(numbers));`

• Random Sampling: Use random sampling techniques to select numbers from a range without replacemen...read more

Build a Python API for document processing using a web framework like Flask or FastAPI.

• Choose a framework: Flask or FastAPI are popular choices for building APIs.

• Set up the project structure: Create directories for routes, models, and services.

• Define API endpoints: Use decorators to define routes for document upload and processing.

• Implement document processing logic: Use libraries like PyPDF2 or docx to read and process documents.

• Handle file uploads: Use multipart/form-data f...read more

Find the maximum distance between any two leaf nodes of a binary tree.

• Traverse the tree to find the maximum depth of left and right subtrees

• Calculate the maximum distance by adding the depths of left and right subtrees

I follow best software practices like unit testing, CI/CD, and Scrum to ensure quality and efficiency in my projects.

• Unit Testing: I implement unit tests using frameworks like JUnit or NUnit to ensure individual components function correctly.

• CI/CD: I use tools like Jenkins or GitHub Actions for continuous integration and deployment, automating the build and release process.

• Scrum Practices: I participate in daily stand-ups, sprint planning, and retrospectives to enhance team c...read more