100+ Software Engineer2 Interview Questions and Answers

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

Static keyword is used in programming to declare variables or methods that belong to the class itself, rather than instances of the class.

• Static variables are shared among all instances of a class.

• Static methods can be called without creating an instance of the class.

• Static keyword is used to define constants in a class.

• Static keyword is used in Java, C++, and other programming languages.

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

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

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.

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

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.

Sort elements of an array of strings

• Use a sorting algorithm like quicksort, mergesort, or bubblesort

• Ensure the sorting algorithm is implemented correctly for strings

• Consider using built-in sorting functions in programming languages like sort() in Python

Dijkstra's algorithm is used to find the shortest path in a graph from a starting node to all other nodes.

• Dijkstra's algorithm is a greedy algorithm that finds the shortest path from a starting node to all other nodes in a weighted graph.

• It maintains a set of vertices whose shortest distance from the starting node is known and continually expands this set.

• The algorithm uses a priority queue to select the vertex with the smallest distance and updates the distances of its neigh...read more

Design a car rental system at a low level

• Use object-oriented programming to model cars, customers, rentals, etc.

• Implement a database to store information about available cars, customer bookings, etc.

• Include features like booking, returning, and searching for cars

• Consider implementing a pricing system based on factors like car type, duration of rental, etc.

Implementing a game using ReactJS involves creating components for game elements, managing state, handling user interactions, and updating the UI.

• Create separate components for game elements such as game board, player pieces, and score display.

• Use React state to manage game state, such as player turns, scores, and game progress.

• Handle user interactions, such as clicking on game pieces or buttons, to update game state.

• Update the UI dynamically based on game state changes to pr...read more

Minimum platforms required to avoid train collisions

• Calculate the number of trains arriving and departing at each time slot

• Find the maximum number of trains present at any given time

• The minimum platforms required will be the maximum number of trains present at any given time

Reverse words in a string

• Split the string into an array of words

• Reverse the array

• Join the array into a string

Count the number of times a specific substring appears in a given string.

• Use a loop to iterate through the string and check for the substring at each position.

• Use a counter variable to keep track of the number of times the substring is found.

• Consider using built-in string functions or regular expressions for efficient counting.

• Example: Given string 'hellohellohello' and substring 'hello', the count would be 3.

To make an object immutable, use final keyword for class, private final keyword for fields, and no setter methods.

• Declare the class as final to prevent inheritance

• Declare all fields as private and final to prevent modification

• Do not provide any setter methods to modify the fields

• If the fields are mutable objects, return a copy of the object instead of the original reference

SQL queries using group by and order by

• Use GROUP BY to group rows that have the same values into summary rows

• Use ORDER BY to sort the result set in ascending or descending order

• Example: SELECT department, COUNT(*) FROM employees GROUP BY department ORDER BY COUNT(*) DESC

Designing a scalable and efficient e-commerce platform for online shopping.

• Use microservices architecture for scalability and flexibility

• Implement caching mechanisms to improve performance

• Utilize a robust database system for storing product information and user data

• Integrate payment gateways for secure transactions

• Implement search and recommendation algorithms for personalized user experience

Reverse a linked list using iterative approach

• Initialize three pointers: current, prev, and next

• Iterate through the linked list, updating pointers to reverse the list

• Return the new head of the reversed linked list

BookMyShow app allows users to book movie tickets, events, and experiences online.

• User-friendly interface for browsing and booking tickets

• Integration with payment gateways for secure transactions

• Personalized recommendations based on user preferences

• Real-time updates on ticket availability and showtimes

• Option to select seats and add-ons for enhanced experience

HashMap is a data structure that stores key-value pairs and uses hashing to retrieve values quickly.

• HashMap uses an array of buckets to store key-value pairs.

• Each bucket contains a linked list of entries with the same hash code.

• When a key-value pair is added, its hash code is used to determine the bucket and the entry is added to the linked list.

• When a value is retrieved, the key's hash code is used to find the bucket and the linked list is searched for the entry with the mat...read more

The code will output 'Hello World!'

• The code is a simple print statement

• It will output the string 'Hello World!'

Low level design implementation involves detailed planning and coding of individual components of a software system.

• Break down the system into smaller components/modules

• Define the interfaces and interactions between components

• Implement each component with attention to detail and efficiency

• Consider factors like performance, scalability, and maintainability

• Test each component thoroughly to ensure functionality and integration

Optimising indexes in Postgres involves understanding query patterns and using tools like EXPLAIN to analyze performance.

• Understand the query patterns to determine which indexes are necessary

• Use tools like EXPLAIN to analyze query performance and identify areas for optimization

• Consider using composite indexes for queries that involve multiple columns

• Regularly monitor and maintain indexes to ensure optimal performance

Use Dutch National Flag algorithm to sort the array in one pass.

• Initialize three pointers low, mid, high at start, iterate through array

• If arr[mid] is 0, swap arr[low] and arr[mid], increment low and mid

• If arr[mid] is 1, increment mid

• If arr[mid] is 2, swap arr[mid] and arr[high], decrement high

• Continue until mid crosses high

LLD of a Movie Ticketing Platform involves designing the system architecture and components for booking and managing movie tickets.

• Design a scalable system with modules for user authentication, movie selection, seat reservation, payment processing, and ticket generation.

• Use a database to store movie details, user information, seat availability, and transaction records.

• Implement APIs for communication between frontend and backend systems.

• Include features like seat selection, b...read more

Try catch resource block is used in Java to automatically close resources after they are no longer needed.

• Try catch resource block is used to manage resources that need to be closed after use, such as file streams or database connections.

• The resources declared within the try block are automatically closed at the end of the block, even if an exception is thrown.

• Example: try (FileInputStream fis = new FileInputStream("file.txt")) { // code that uses fis } catch (IOException e) ...read more

Design a database for a travel app to store user information, bookings, reviews, and destinations.

• Create tables for users, bookings, reviews, and destinations

• Include columns for user details, booking information, review ratings, and destination details

• Establish relationships between tables using foreign keys

• Consider indexing commonly queried fields for faster retrieval

• Implement data validation to ensure data integrity

Detect cycle in a linked list using Floyd's Tortoise and Hare algorithm

• Use two pointers, slow and fast, to traverse the linked list

• If there is a cycle, the fast pointer will eventually meet the slow pointer

• Time complexity is O(n) and space complexity is O(1)

A valid binary search tree is a binary tree where the left subtree of a node contains only nodes with keys less than the node's key, and the right subtree only nodes with keys greater than the node's key.

• Nodes in the left subtree of a node must have keys less than the node's key.

• Nodes in the right subtree of a node must have keys greater than the node's key.

• In-order traversal of the tree should result in a sorted list of keys.

Implement a function to reverse a string in Go lang

• Create a function that takes a string as input

• Convert the string into a slice of bytes for easier manipulation

• Use a loop to iterate through the slice and reverse the order of characters

• Convert the reversed slice back into a string and return it

Real-time operating systems are designed to provide guaranteed response times for critical tasks.

• Real-time operating systems prioritize tasks based on their urgency and importance.

• They are commonly used in industries such as aerospace, automotive, and industrial automation.

• Examples include VxWorks, QNX, and FreeRTOS.

Priority queue can be implemented using a heap data structure.

• Create a min heap or max heap based on the priority order needed.

• Insert elements into the heap based on their priority level.

• Remove elements from the heap based on their priority level.

• Heapify the heap after each insertion or deletion operation.

• Example: Implementing a min heap for a priority queue where lower values have higher priority.

Implementing search functionality in a React application

• Use state to store search query

• Filter data based on search query

• Display filtered results

Find the maximum value in a sliding window of a given size in an array.

• Use a deque to store indices of elements in the current window

• Keep the deque sorted in decreasing order of element values

• Pop elements from the deque that are out of the current window

• The front of the deque will always have the maximum element in the window

Zig Zag Tree Traversal is a method of traversing a binary tree in a zig-zag pattern.

• Start traversal from the root node

• Alternate between going left and right at each level

• Use a stack or queue data structure for traversal

• Example: For a binary tree with nodes 1, 2, 3, 4, 5, the zig-zag traversal would be 1, 3, 2, 4, 5

Frequency Tracker class to track frequencies of elements

• Create a class with a data structure to store elements and their frequencies

• Implement methods to add elements, remove elements, and get frequency of elements

• Use a hashmap to store elements as keys and their frequencies as values

GC collector in Java is responsible for managing memory by reclaiming unused objects and freeing up memory space.

• GC stands for Garbage Collector

• Automatically manages memory by reclaiming unused objects

• Prevents memory leaks and optimizes memory usage

• Different types of GC algorithms like Serial, Parallel, CMS, G1

• Example: System.gc() can be used to suggest garbage collection

Jira is a project management tool used for issue tracking, task management, and agile project management.

• Jira allows users to create and track issues, assign tasks, and prioritize work.

• It supports agile methodologies like Scrum and Kanban.

• Users can customize workflows, create dashboards, and generate reports.

• Integration with other tools like Confluence, Bitbucket, and Slack is possible.

HTTP verbs are used to indicate the action to be performed on a resource in a RESTful API.

• GET - Retrieve data from a server

• POST - Send data to a server to create/update a resource

• PUT - Update a resource on the server

• DELETE - Remove a resource from the server

• PATCH - Update a resource partially

Multithreading in Java allows multiple threads to execute concurrently, improving performance and responsiveness.

• Multithreading is achieved in Java by extending the Thread class or implementing the Runnable interface.

• Threads share the same memory space, allowing them to communicate and synchronize using methods like wait(), notify(), and notifyAll().

• Java provides high-level concurrency utilities like Executors and ThreadPoolExecutor for managing thread pools.

• Care must be take...read more

Hoisting is a JavaScript mechanism where variable and function declarations are moved to the top of their containing scope during compilation.

• Variable and function declarations are hoisted to the top of their scope.

• Only declarations are hoisted, not initializations.

• Function declarations take precedence over variable declarations.

Print the Fibonacci series

• Use a loop to generate Fibonacci numbers

• Start with 0 and 1, then add the previous two numbers to get the next number

• Repeat this process until reaching the desired length of the series

Reverse a linked list by changing the pointers direction

• Iterate through the linked list and change the direction of pointers

• Use three pointers - prev, current, next to reverse the list

• Update the head of the linked list to the last node after reversing