10+ McKinsey & Company Interview Questions and Answers

Implement clean coding practices for calculating total cost of energy consumption on shared project.

• Follow naming conventions for variables and functions to make the code more readable (e.g. use descriptive names like 'calculateTotalCost' instead of 'calc')

• Break down the feature into smaller functions to improve code reusability and maintainability

• Use comments to explain complex logic or algorithms for better understanding by other team members

• Write unit tests to ensure the a...read more

BookMyShow is an online platform for booking movie tickets and event tickets.

• BookMyShow allows users to browse and book tickets for movies, plays, concerts, and other events.

• The system should have a user-friendly interface for easy navigation and booking.

• It should also have a secure payment gateway for online transactions.

• The system should be scalable to handle a large number of users and transactions.

• It should also have features like seat selection, cancellation, and refund....read more

TDD stands for Test-Driven Development, which involves writing test cases before writing the actual code.

• TDD is a software development process where tests are written before the code implementation.

• Test cases are written based on the expected behavior of the code.

• Developers write just enough code to pass the tests, ensuring code quality and functionality.

• TDD helps in identifying bugs early in the development process.

• Examples: JUnit, NUnit, and pytest are popular testing frame...read more

Current project involves developing a cloud-based CRM system for a multinational corporation.

• Utilizing microservices architecture for scalability and flexibility

• Implementing RESTful APIs for seamless integration with other systems

• Leveraging cloud services like AWS for hosting and data storage

• Using Docker containers for easy deployment and management

Performance improvement techniques in ReactJS involve code splitting, lazy loading, optimizing render methods, and using memoization.

• Implement code splitting to load only necessary code for each route or component

• Utilize lazy loading to defer loading of non-essential components until they are needed

• Optimize render methods by avoiding unnecessary re-renders and using PureComponent or shouldComponentUpdate

• Use memoization techniques like useMemo or useCallback to prevent unneces...read more

Certain designs are chosen for their functionality, aesthetics, and user experience.

• Certain designs are chosen based on the specific needs and requirements of the project or product.

• Designs are often selected for their ability to enhance usability and user experience.

• Aesthetics play a key role in design choices, as visually appealing designs can attract and engage users.

• Some designs are preferred for their efficiency and effectiveness in achieving the desired goals.

• Considerat...read more

LLD system design for a restaurant involves designing the software architecture for managing orders, inventory, reservations, and customer data.

• Consider designing separate modules for order management, inventory tracking, reservation system, and customer database.

• Implement features like menu management, table allocation, payment processing, and reporting functionalities.

• Ensure scalability and performance by optimizing database queries, using caching mechanisms, and implementi...read more

Virtual DOM is a lightweight copy of the actual DOM in React, used for efficient updates.

• Virtual DOM is a concept where a lightweight copy of the actual DOM is created in memory.

• React uses Virtual DOM to improve performance by minimizing actual DOM updates.

• When state or props change, React compares the Virtual DOM with the actual DOM and only updates the necessary parts.

• This helps in reducing the number of DOM manipulations and improves overall performance.

Promises and closures are important concepts in JavaScript for handling asynchronous operations and maintaining scope.

• Promises are objects representing the eventual completion or failure of an asynchronous operation.

• Closures are functions that have access to variables from their containing scope even after the parent function has finished executing.

• Promises can be used to handle asynchronous operations like fetching data from a server.

• Closures are commonly used in event handl...read more

Best coding practices involve writing clean, efficient, and maintainable code.

• Use meaningful variable and function names

• Follow consistent coding style and formatting

• Write comments to explain complex logic

• Avoid duplicate code by using functions and classes

• Test code thoroughly before deployment

Designing a test plan for a problem

• Identify the problem statement and objectives

• Define test scope and criteria

• Create test cases based on requirements

• Assign resources and timelines for testing

• Execute test cases and document results