90+ Software Engineer2 Interview Questions and Answers

Answering technical questions for Software Engineer 2 position

• To determine if a point is inside or outside a 2-manifold, use the ray casting algorithm

• To merge closeby points, use clustering algorithms like k-means or DBSCAN

• To determine if the normals of two triangles are wrongly oriented, use the cross product of their edges

• Favorite research paper and why

To process large amount of data, use tools like Apache Hadoop, Apache Spark, or Google BigQuery.

• Utilize distributed computing frameworks like Apache Hadoop or Apache Spark for parallel processing of data

• Consider using cloud-based solutions like Google BigQuery for scalability and cost-effectiveness

• Optimize data processing pipelines by using tools like Apache Kafka for real-time data streaming

• Implement data compression techniques to reduce storage and processing overhead

Find pair of elements in array whose sum is equal to target k.

• Use a hashmap to store the difference between target k and each element in the array.

• Iterate through the array and check if the current element's complement exists in the hashmap.

• Return the indices of the pair that sums up to target k.

To find duplicates in an array of strings in linear time

• Create a hash table to store the frequency of each string

• Iterate through the array and check if the frequency of any string is greater than 1

• If yes, then it is a duplicate

• Return true if duplicates are found, else false

Optimise frequently searched items list by implementing caching, indexing, and prioritising popular items.

• Implement caching to store frequently searched items in memory for quick access.

• Use indexing to efficiently search and retrieve items from the list.

• Prioritise popular items by tracking search frequency and displaying them prominently.

• Consider implementing autocomplete or predictive search to suggest items as users type.

• Regularly update the list based on search trends to e...read more

Creating custom hook, explaining virtual DOM, sorting an array in React

• To create a custom hook in React, you can define a function that starts with 'use' and can be reused across components.

• React's virtual DOM is a lightweight copy of the actual DOM, which allows React to efficiently update the real DOM.

• To sort an array in JavaScript, you can use the built-in 'sort' method or write a custom sorting function.

Generate string permutations with first letter as vowel and atleast 3 letters

• Create a list of vowels and a list of consonants

• Generate all possible permutations of length 3 or more using itertools.permutations

• Filter out permutations that do not start with a vowel

• Join the remaining permutations into strings

Process large amount of logs by using log aggregation tools like ELK stack or Splunk.

• Utilize log aggregation tools like ELK stack (Elasticsearch, Logstash, Kibana) or Splunk to collect, index, search, and visualize logs.

• Implement proper log rotation and retention policies to manage the volume of logs efficiently.

• Leverage distributed systems and parallel processing to handle large volumes of logs effectively.

• Use filtering and parsing techniques to extract relevant information ...read more

The task is to find the frequency of subsequent characters in a given input string.

• Iterate through the input string while keeping track of the current character and its frequency.

• If the current character is the same as the previous character, increment the frequency count.

• If the current character is different, append the previous character and its frequency to the output string.

• Repeat until the end of the input string is reached.

Concatenate 3 columns and handle null values in SQL query

• Use CONCAT_WS function to concatenate columns and handle null values

• Provide a separator as the first argument in CONCAT_WS function

• Use IFNULL function to replace null values with a specified value

I am interested in technologies related to artificial intelligence, machine learning, and cloud computing.

• Artificial Intelligence

• Machine Learning

• Cloud Computing

Coding challenges with screen sharing involve solving programming problems while sharing your screen with an interviewer.

• Prepare by practicing coding challenges beforehand

• Ensure your internet connection and screen sharing software are working properly

• Communicate your thought process and ask questions during the challenge

• Test your code thoroughly before submitting

• Be open to feedback and suggestions from the interviewer

Standard ADSO is for persistent storage and reporting, while write optimized DSO is for temporary storage. Keys in ADSO are used for data modeling and performance optimization.

• Standard ADSO is used for persistent storage and reporting, while write optimized DSO is used for temporary storage before loading data to a standard ADSO.

• Write optimized DSO does not store data persistently, making it suitable for temporary data storage during data loads.

• Keys in ADSO are defined to uni...read more

Abstract class can have both abstract and non-abstract methods, while interface can only have abstract methods.

• Abstract class can have constructors, fields, and methods, while interface can only have constants and method signatures.

• A class can extend only one abstract class, but can implement multiple interfaces.

• Abstract classes are used to define a common behavior for subclasses, while interfaces are used to define a contract for classes to implement.

• Example: Abstract class ...read more

To check load issue and spamming, monitor server performance, analyze traffic patterns, implement CAPTCHA, and use machine learning algorithms.

• Monitor server performance to identify any spikes in traffic or unusual activity

• Analyze traffic patterns to detect any abnormal behavior or patterns consistent with spamming

• Implement CAPTCHA or other verification methods to prevent automated spamming

• Utilize machine learning algorithms to continuously learn and adapt to new spamming tec...read more

String manipulation using loops and conditionals for software engineering

• Use loops to iterate through each character in the string

• Use conditional statements to check for specific conditions and manipulate the string accordingly

• Examples: reversing a string, counting occurrences of a specific character, removing whitespace

Sharding the database is based on factors like scalability, performance, and data distribution.

• Consider sharding when the database is growing rapidly and needs to handle increased load.

• Shard based on geographical location to reduce latency for users in different regions.

• Shard based on specific data types or access patterns to optimize performance.

• Consider sharding when the database becomes too large to efficiently handle queries and transactions.

• Evaluate the trade-offs betwee...read more

The number of ways to reach the rightmost cell from the topmost cell in a 2D matrix can be calculated using dynamic programming.

• Use dynamic programming to calculate the number of ways to reach each cell in the matrix.

• At each cell, the number of ways to reach it is the sum of the number of ways to reach the cell above it and the cell to the left of it.

• The value in the rightmost cell will give the total number of ways to reach it from the topmost cell.

var, let, and const are all used for variable declaration in JavaScript, but they have different scopes and mutability.

• var is function-scoped and can be redeclared and reassigned

• let is block-scoped and can be reassigned but not redeclared

• const is block-scoped and cannot be reassigned or redeclared

Paytm uses microservices architecture for scalability and flexibility in system design.

• Paytm's system design is based on microservices architecture to break down the application into smaller, independent services.

• Each service in Paytm's architecture handles a specific function, such as payments, wallet, or shopping.

• Microservices communicate with each other through APIs, allowing for easier scalability and maintenance.

• This architecture enables Paytm to quickly add new features...read more

No, an abstract class can have concrete methods as well.

• An abstract class can have both abstract and concrete methods.

• Abstract methods are meant to be implemented by subclasses, while concrete methods can have a default implementation.

• Having only abstract methods in an abstract class is not a requirement.

Check if rectangles overlap by comparing their coordinates

• Compare the x and y coordinates of the two rectangles to see if they overlap

• If one rectangle is to the left of the other, or above the other, they do not overlap

• If the rectangles overlap, the x and y ranges will intersect

Designing an e2e payment system with detailed component explanation

• 1. Define user roles and permissions (e.g. customer, merchant, admin)

• 2. Implement secure payment gateway integration (e.g. Stripe, PayPal)

• 3. Develop user-friendly interfaces for payment processing

• 4. Ensure data encryption and compliance with PCI DSS standards

• 5. Set up automated payment notifications and transaction tracking

Design APIs for user generated content to allow users to create, read, update, and delete their own content.

• Create API endpoint for users to create new content

• Read API endpoint to retrieve user's content

• Update API endpoint to allow users to modify their content

• Delete API endpoint to enable users to remove their content

DNS (Domain Name System) is a system that translates domain names to IP addresses. UTS (User Thread Scheduler) architecture manages user-level threads.

• DNS is used to translate human-readable domain names (like www.example.com) to IP addresses (like 192.0.2.1).

• DNS operates through a distributed database system that stores domain name records.

• UTS architecture manages user-level threads in a multi-threaded environment, allowing for efficient scheduling and execution.

• UTS architec...read more

To delete a node in a linked list with a given pointer, update the node's value and next pointer to the next node's value and next pointer.

• Set the value of the node to the value of the next node

• Set the next pointer of the node to the next node's next pointer

Yes, I enjoy solving puzzles as it challenges my problem-solving skills.

• I enjoy the mental challenge of puzzles

• It helps me improve my problem-solving skills

• Examples: Sudoku, crosswords, logic puzzles

Writing code on notepad instead of an IDE

• Ensure proper indentation and formatting

• Use comments to explain code

• Compile and test code manually

• Save frequently to avoid losing work

I handle pressure by prioritizing tasks, staying organized, seeking support when needed, and practicing stress-relief techniques.

• Prioritize tasks based on deadlines and importance

• Stay organized with to-do lists and calendars

• Seek support from colleagues or supervisors when feeling overwhelmed

• Practice stress-relief techniques such as deep breathing or exercise

• Maintain a positive attitude and focus on problem-solving

Currying in JavaScript is a technique of transforming a function that takes multiple arguments into a sequence of functions, each taking a single argument.

• Create a function that takes a single argument and returns a new function that takes the next argument.

• Repeat this process until all arguments are received and then return the final result.

• Example: function sum(a) { return function(b) { return function(c) { return function(d) { return a + b + c + d; }; }; }; } sum(1)(2)(3)(...read more

Cloning a singly linked list with random pointers involves creating a deep copy of the list while maintaining the random pointers.

• Create a new node for each node in the original list and insert it next to the original node.

• Update the random pointers of the new nodes to point to the corresponding new nodes.

• Separate the original and cloned lists by adjusting the next pointers.

Generate permutations of a given string

• Use recursion to generate all possible permutations

• Swap characters in the string to create different permutations

• Base case: when the string length is 1, return the string as a permutation

Find the maximum subarray sum using Kadane's algorithm

• Initialize max_sum and current_sum to 0

• Iterate through the array and update current_sum by adding the current element

• If current_sum becomes negative, reset it to 0

• Update max_sum if current_sum is greater than max_sum

Use GROUP BY to find distinct values in SQL without using the DISTINCT keyword.

• Use GROUP BY clause with all columns in the SELECT statement

• This will group the rows with the same values together, effectively giving distinct values

Two entities for cross site sale promotion are affiliate marketing platform and customer loyalty program.

• Affiliate marketing platform: Allows businesses to partner with affiliates who promote their products on their own websites in exchange for a commission.

• Customer loyalty program: Rewards customers for repeat purchases or other actions, encouraging them to continue shopping with the brand.

Branching strategies in Agile methodologies involve creating separate branches for different features or tasks to enable parallel development.

• Feature branching: Each feature or user story is developed in a separate branch, allowing for isolation and independent testing.

• Release branching: A branch is created for each release, enabling bug fixes and maintenance to be done separately from ongoing development.

• Task branching: Developers create branches for individual tasks or sub-...read more

Microservices architecture is a design pattern where an application is composed of small, independent services that communicate over well-defined APIs.

• Each microservice is responsible for a specific business function or capability

• Services are loosely coupled and can be developed, deployed, and scaled independently

• Communication between services is typically done through lightweight protocols like HTTP or messaging queues

• Microservices architecture promotes flexibility, scalabil...read more

ES6, also known as ECMAScript 2015, is the sixth major release of the JavaScript language that introduced new features and syntax improvements.

• Introduced let and const for variable declarations

• Added arrow functions for more concise syntax

• Included classes for object-oriented programming

• Introduced template literals for easier string interpolation

• Added default parameters and rest parameters for functions

Memory concepts in C and IPC involve understanding memory management in C programming and inter-process communication techniques.

• Memory management in C involves concepts like stack, heap, and static memory allocation.

• IPC techniques include shared memory, message queues, and semaphores for communication between processes.

• Understanding pointers and memory allocation is crucial for efficient memory management in C programming.

• Examples: Using malloc() and free() for dynamic memor...read more

Implement BFS algorithm to find the nearest neighbour

• Create a queue to store nodes to be visited

• Start with the initial node and add it to the queue

• While the queue is not empty, dequeue a node, visit its neighbours, and add them to the queue

• Repeat until the nearest neighbour is found

DFS is a graph traversal algorithm that explores as far as possible along each branch before backtracking.

• DFS stands for Depth First Search.

• It starts at the root node and explores as far as possible along each branch before backtracking.

• It uses a stack to keep track of the visited nodes.

• It can be implemented recursively or iteratively.

• It is used in finding connected components, topological sorting, and solving puzzles like the maze problem.

Kadane's Algorithm is used to find the maximum sum of a contiguous subarray within an array of integers.

• Initialize two variables: max_so_far and max_ending_here to track the maximum sum.

• Iterate through the array and update max_ending_here by adding the current element or starting a new subarray.

• Update max_so_far if max_ending_here becomes greater than max_so_far.

• Return max_so_far as the maximum subarray sum.

Reverse a linked list in k sizes

• Break the linked list into groups of size k

• Reverse each group individually

• Connect the reversed groups back together

Stateless widgets do not store any state information, while stateful widgets can hold and update state data.

• Stateless widgets are immutable and do not change their state during the build process.

• Stateful widgets can hold and update state data, causing them to rebuild when the state changes.

• Stateless widgets are more efficient as they do not need to manage state information.

• Stateful widgets are useful for interactive UI components that need to update based on user input.

• Exampl...read more

Move all 0s to the end of the array while maintaining the order of other elements.

• Iterate through the array and keep track of the index to place non-zero elements.

• After iterating, fill the remaining positions with 0s.

OOPs concept and finding duplicates in an array of strings

• Explain OOPs concepts like inheritance, polymorphism, encapsulation, and abstraction

• To find duplicates in an array of strings, use a HashSet to store unique elements and a List to store duplicates

• Iterate through the array and check if the element is already in the HashSet, if yes, add it to the List of duplicates

React's virtual DOM is a lightweight copy of the actual DOM, used for efficient updates and rendering.

• Virtual DOM is a representation of the actual DOM in memory.

• React compares the virtual DOM with the actual DOM to determine the minimal changes needed for updates.

• Changes are then batched and applied to the actual DOM for efficient rendering.