90+ Interview Questions and Answers

To design a website displaying top 1000 products with real-time rating updates, use a combination of backend and frontend technologies.

• Implement a backend system to fetch and update product ratings from a database or API.

• Use a frontend framework like React or Angular to create a dynamic user interface.

• Implement pagination or lazy loading to handle the large number of products.

• Optimize the website for performance by caching frequently accessed data.

• Consider using websockets or...read more

Implement a specialStack class with O(1) push, pop, and minimum element retrieval.

• Use an additional stack to keep track of the minimum element at each step.

• When pushing an element, compare it with the top of the minimum stack and update if necessary.

• When popping an element, also pop from the minimum stack if the popped element is the current minimum.

Find a pair of integers in an array whose sum is equal to a given number.

• Iterate through the array and for each element, check if the difference between the given number and the current element exists in the array.

• Use a hash set to store the elements of the array for efficient lookup.

• Return the pair of integers if found, otherwise return a message indicating no such pair exists.

Find repeating numbers in an array of n elements containing numbers from 0 to n-1 in O(n) time and constant memory space.

• Create an empty result array.

• Iterate through the array and for each element, take its absolute value and subtract 1 from it.

• If the element at the new index is positive, make it negative.

• If it is already negative, add the original element to the result array.

• Return the result array.

Program to calculate total number of valid words possible from a given word and dictionary

• Create a hash table of dictionary words

• Generate all possible permutations of the given word

• Check if each permutation is a valid word in the hash table

• Return the count of valid words

The Lowest Common Ancestor (LCA) of two nodes in a binary tree is the deepest node that is a common ancestor of both nodes.

• Start from the root node and traverse the tree to find the given nodes.

• Store the paths from the root to each node.

• Compare the paths to find the last common node, which is the LCA.

Find the point closest to a given point P among a million points.

• Preprocess the million points to calculate their distances from P.

• Store the distances and corresponding points in a data structure.

• Sort the distances in ascending order.

• Return the point corresponding to the smallest distance.

I chose the technologies based on their compatibility with the project requirements and my familiarity with them.

• Chose React for front-end development due to its component-based architecture and ease of use

• Used Node.js for back-end development because of its non-blocking I/O and scalability

• Selected MongoDB as the database for its flexibility with unstructured data and ease of integration

The virtual keyword is used in C++ for creating virtual functions and implementing polymorphism.

• Used to create virtual functions that can be overridden by derived classes

• Allows for dynamic binding of functions at runtime

• Used in implementing polymorphism

• Can be used with multiple inheritance to resolve ambiguity

• Example: virtual void functionName() = 0; creates a pure virtual function

I am interested in working with web apps.

• Web apps have a wider reach and are more accessible.

• They can be accessed from anywhere with an internet connection.

• Web apps are easier to update and maintain.

• Examples: Facebook, Google Docs, Amazon

Program to find GCD of a set of numbers using Euclid's algorithm.

• Take two numbers and find their GCD using Euclid's algorithm.

• Repeat the process for all numbers in the set.

• The final GCD will be the GCD of the entire set.

• Use recursion to simplify the code.

• If any number is 0, return the other number as GCD.

The puzzle involves finding the fastest 3 horses out of 25, using only 5 lanes for races.

• Divide the horses into groups of 5 and race them, identifying the fastest horse in each group.

• Race the fastest horses from each group to identify the overall fastest horse.

• Race the second fastest horse from each group to identify the second fastest overall horse.

• Race the third fastest horse from each group against the two remaining untested horses to identify the third fastest overall hor...read more

IAAS, PAAS, and SAAS are different cloud computing models that offer varying levels of control and management to users.

• IAAS (Infrastructure as a Service) provides users with access to virtualized computing resources such as servers, storage, and networking. Users have complete control over the infrastructure and are responsible for managing it.

• PAAS (Platform as a Service) provides users with a platform to develop, run, and manage applications without having to worry about the...read more

Polymorphism is the ability of an object to take on many forms. Other OOPS concepts include inheritance, encapsulation, and abstraction.

• Polymorphism allows objects of different classes to be treated as objects of a common superclass.

• Inheritance allows a class to inherit properties and methods from another class.

• Encapsulation is the bundling of data and methods within a class, hiding the internal details.

• Abstraction focuses on providing only essential information to the outsid...read more

Program to delete a node in a singly linked list given only a pointer to the node to be deleted

• Copy the data from the next node to the current node and delete the next node

• Update the pointer of the current node to point to the next node's next node

• Handle edge cases where the node to be deleted is the last node in the list

Design optimal data structures for LRU cache

• Use a doubly linked list to keep track of recently used items

• Use a hash table to store key-value pairs for quick access

• When an item is accessed, move it to the front of the linked list

• When the cache is full, remove the least recently used item from the back of the linked list and hash table

To measure and ensure not breaching SLA, track performance metrics, set alerts, prioritize tasks, and regularly review and adjust processes.

• Track performance metrics such as response time, uptime, and error rates

• Set up alerts for when performance metrics approach SLA thresholds

• Prioritize tasks based on their impact on SLA compliance

• Regularly review and adjust processes to optimize performance and prevent breaches

Implement automated monitoring and logging to proactively detect errors before customers report them.

• Set up automated monitoring tools to track system performance and detect anomalies

• Implement logging mechanisms to capture errors and exceptions in real-time

• Utilize error tracking software to aggregate and analyze error data

• Establish alerts and notifications for critical errors to prompt immediate action

• Regularly review error logs and performance metrics to identify patterns an...read more

Program to insert an element into a sorted linked list

• Traverse the linked list until the correct position is found

• Create a new node with the element to be inserted

• Adjust the pointers of the previous and next nodes to point to the new node

• Handle edge cases such as inserting at the beginning or end of the list

Intuit is a financial software company known for products like QuickBooks and TurboTax.

• Intuit is a leading provider of financial software solutions for individuals and businesses.

• They are known for products like QuickBooks, TurboTax, and Mint.

• Intuit's software helps users manage their finances, taxes, and accounting efficiently.

• The company focuses on simplifying financial tasks for users through user-friendly interfaces and automation.

• Intuit has a strong reputation for custom...read more

To build low latency systems, focus on optimizing code, reducing network latency, using efficient data structures, and leveraging caching.

• Optimize code by reducing unnecessary computations and improving algorithms

• Reduce network latency by minimizing round trips and using efficient protocols like UDP

• Use efficient data structures like arrays and hash maps for quick access to data

• Leverage caching to store frequently accessed data in memory for faster retrieval

Check if a string of parenthesis is valid or not.

• Use a stack to keep track of opening parenthesis.

• Iterate through the string and push opening parenthesis onto the stack.

• When encountering a closing parenthesis, pop from the stack and check if it matches the corresponding opening parenthesis.

• If stack is empty at the end and all parenthesis have been matched, the string is valid.

C is a procedural language, C++ is an object-oriented language, and Java is a class-based object-oriented language.

• C is a low-level language used for system programming and embedded systems.

• C++ is an extension of C with added features like classes, inheritance, and polymorphism.

• Java is platform-independent and has automatic memory management through garbage collection.

• Java programs run on a virtual machine, while C and C++ programs compile to machine code.

• C++ is often used fo...read more

Web 2.0 is more interactive and user-generated content-driven, while Web 1.0 was static and read-only.

• Web 2.0 allows for social networking and collaboration, while Web 1.0 was primarily informational.

• Web 2.0 relies on user-generated content, while Web 1.0 was created by developers and publishers.

• Web 2.0 is more dynamic and responsive, while Web 1.0 was static and slow to load.

• Examples of Web 2.0 sites include Facebook, Twitter, and Wikipedia, while Web 1.0 sites include early...read more

Success metric is a quantifiable measure used to determine the effectiveness of a product or project.

• Success metric should be aligned with the overall goals and objectives of the product or project.

• It should be specific, measurable, achievable, relevant, and time-bound (SMART).

• Examples of success metrics include revenue growth, customer satisfaction scores, user engagement metrics, and market share.

• Regularly tracking and analyzing the success metrics can help in making data-d...read more

I have prepared over 100 tax returns for individuals and small businesses.

• I have experience preparing both individual and small business tax returns

• I am familiar with various tax forms such as 1040, Schedule C, and Schedule E

• I have worked with clients to maximize deductions and credits

• I have experience with tax software such as TurboTax and TaxAct

Agile working methods involve iterative development, collaboration, flexibility, and continuous improvement.

• Agile methods prioritize customer satisfaction through early and continuous delivery of valuable software.

• Teams work in short iterations called sprints, focusing on delivering working software frequently.

• Collaboration between team members, stakeholders, and customers is essential for success.

• Flexibility to adapt to changing requirements and feedback is a key principle o...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

Design an event driven scheduler for managing tasks and events.

• Use a message queue system to handle incoming events and tasks.

• Implement event listeners to trigger actions based on specific events.

• Utilize a scheduling algorithm to prioritize and manage tasks.

• Include error handling mechanisms to handle failures gracefully.

Convert integer to Roman numeral

• Create a mapping of integer values to Roman numeral symbols

• Iterate through the mapping to find the largest Roman numeral that fits the integer

• Subtract the value of the Roman numeral from the integer and repeat until the integer becomes 0

LRU cache is a data structure that stores the most recently used items, discarding the least recently used items when full.

• Use a doubly linked list to keep track of the order of items based on their usage.

• Use a hash map to quickly access items in the cache.

• When a new item is accessed, move it to the front of the linked list. If the cache is full, remove the item at the end of the list.

Normalization is the process of organizing data in a database to reduce redundancy and improve data integrity.

• Normalization involves breaking down a table into smaller tables and establishing relationships between them.

• There are different levels of normalization, with each level addressing a specific type of data redundancy.

• Normalization helps to prevent data inconsistencies and anomalies, and improves database performance.

• Example: A customer table can be normalized into a cu...read more

Polymorphism is the ability of a function or method to behave differently based on the object it is acting upon.

• Polymorphism allows objects of different classes to be treated as objects of a common superclass.

• There are two types of polymorphism: compile-time (method overloading) and runtime (method overriding).

• Example: Inheritance allows a child class to override a method from its parent class, exhibiting polymorphic behavior.

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.

ITIL stands for Information Technology Infrastructure Library, a set of best practices for IT service management.

• ITIL provides a framework for organizations to plan, deliver, and support IT services.

• It consists of five core publications covering different aspects of IT service management.

• ITIL processes include incident management, problem management, change management, and more.

• ITIL helps organizations improve efficiency, reduce costs, and enhance customer satisfaction.

• Certif...read more

Design a system to match users with the nearest available driver like Uber.

• Use geolocation data from both users and drivers to calculate distances.

• Implement a matching algorithm to pair users with the nearest available driver.

• Consider factors like traffic conditions, driver availability, and user preferences.

• Utilize real-time updates to continuously update driver availability and user locations.