Google Interview Questions By Scholarhat

1. Top Google Interview Questions and How to Answer Them Google Interview Questions Studying for Google interview Questions can be difficult, especially because the requirements for getting a job as a software engineer are very high. These Google interview questions contain crucial Google interview questions for software engineers, insights into Google interview questions for freshers, and the most recent Google interview questions for 2024. With these materials, you'll be better able to handle each step of the interview and successfully demonstrate your talents. Start learning the Interview Question tutorial; you will learn different types of interview questions that are mostly asked in your Google Interview, including understanding the Google Interview Process,  Google interview questions for freshers, Google Programming Languages Interview Questions, and a lot more.  What should you expect in Google Interviews?

2. You can expect in Google interviews: Technical Questions: Solve coding problems focusing on algorithms and data structures. System Design: Design scalable and efficient systems (for experienced roles). Behavioral Questions: Share examples of how you handle challenges and work in teams. Culture Fit: Show how you align with Google’s values of teamwork and innovation. Understand the Google Interview Process Section Description Eligibility Criteria Relevant degree (e.g., B.Tech, MCA) Strong academic record Coding experience (for technical roles) Online Application Submit your resume via Google's career portal Fill in personal and educational details Provide coding samples applicable) or portfolio (if

3. Recruitment Process Resume screening Online coding assessment (if applicable) Technical interviews HR interview Interview Rounds Phone Screen (Coding & behavioral questions) On-site Interviews (Technical & behavioral) Interview Questions Technical (Freshers) Solve coding problems on data structures & algorithms -Basic programming knowledge (e.g., arrays, strings, sorting) Technical (Experienced) Interview Questions System design questions Problem-solving on scalability & optimization Advanced algorithms and data structures HR Interview Questions Why do you want to work at Google? Tell me about a challenging project. How do you handle teamwork or conflict? What is your greatest strength? Where do you see yourself in 5 years? Google interview questions for freshers Here, we will discuss some of the most important basic interview questions for freshers that are beneficial for you all. Q 1. Write a program to reverse a string. To reverse a string, you can use built-in functions or loop constructs, depending on the language. Here's how you can reverse a string in C#, Java, C++, and Python: Example

4. C++ C# Python Java #include <iostream> #include <algorithm> using namespace std; string reverseString(string str) { } reverse(str.begin(), str.end()); return str; int main() { } string input = "hello"; cout << "Reversed string: " << reverseString(input) << endl; return 0; Run Code >> Output Reversed string: olleh Q 2. Write a program to check whether a string is a palindrome. A palindrome is a word, phrase, or sequence that reads the same backward as forwards. Here's how you can check if a string is a palindrome in different languages. Example C++ C# Python Java

5. #include <iostream> #include <algorithm> using namespace std; bool isPalindrome(string str) { } string reversed = str; reverse(reversed.begin(), reversed.end()); return str == reversed; int main() { } string input = "madam"; cout << "Is palindrome: " << isPalindrome(input) << endl; return 0; Run Code >> Output Is palindrome: True Q 3. Write a program to find the maximum element in an array. You can iterate through the array and track the largest element. Example C++ C# Python Java

6. #include <iostream> #include <algorithm> using namespace std; int findMax(int arr[], int size) { } return *max_element(arr, arr + size); int main() { } int arr[] = {1, 5, 3, 9, 2}; int size = sizeof(arr) / sizeof(arr[0]); cout << "Maximum element: " << findMax(arr, size) << endl; return 0; Run Code >> Output Maximum element: 9 Q 4. Write a program to generate the nth Fibonacci number. The Fibonacci sequence starts with 0 and 1, and each subsequent number is the sum of the two preceding ones. Read more: How to Implement Fibonacci Series in C# Example C++ C# Python Java

7. #include <iostream> usingnamespace std; int fibonacci(int n) { } if (n <= 1) return n; return fibonacci(n - 1) + fibonacci(n - 2); int main() { } int n = 5; cout << "Fibonacci of " << n << ": " << fibonacci(n) << endl; return 0; Run Code >> Output Fibonacciof 5: 5 Q 5. Write a program to find the factorial of a number. The factorial of a number is the product of all positive integers less than or equal to that number. ExamplefF C++ C# Python Java

8. #include <iostream> usingnamespace std; int factorial(int n) { } if (n == 0 || n == 1) return 1; return n * factorial(n - 1); int main() { } int number = 5; cout << "Factorial of " << number << ": " << factorial(number) << endl; return 0; Run Code >> Output Factorialof 5: 120 Q 6. Write a program to find the missing number in an array. The sum of the integers from 1 to n equals (n * (n + 1)) / 2. Subtracting the sum of the entries in the array from the overall sum yields the missing integer. Example C++ C# Python Java

9. #include <iostream> usingnamespace std; int findMissingNumber(int arr[], int n) { } int totalSum = n * (n + 1) / 2; int arrSum = 0; for (int i = 0; i < n - 1; i++) { arrSum += arr[i]; } r e t u r n t o t a l S u m - a r r S u m ; int main() { } int arr[] = { 1, 2, 4, 5, 6 }; int n = 6; cout << "Missing number: " << findMissingNumber(arr, n) << endl; return 0; Run Code >> Output Missing number: 3 Google Programming Languages Interview Questions Q 1. What are the differences between Java and C#? Java and C# are both object-oriented languages but differ in their platform dependency. Java is platform-independent at runtime and is used with the JVM, whereas C# is primarily used with the .NET framework on Windows. C# has properties, events, and a for each loop for collection traversal, while Java uses getter/setter methods and has a simpler event model. Q 2. What is the difference between == and === in JavaScript? In JavaScript, == checks for equality after type conversion, while === checks for strict equality without type conversion. For instance, 5 == '5' is true because of type conversion, but 5 === '5' is

10. false. Q 3. How does Python handle memory management? Python uses automatic garbage collection through reference counting and a cyclic garbage collector. It manages memory allocation dynamically, using __del__ destructors less often than languages like C++. Q 4. What is the difference between an interface and an abstract class in Java? An abstract class in Java can have method implementations, but an interface can only have method declarations (prior to Java 8). Multiple interfaces can be implemented by a class, but only one abstract class can be extended. Q 5. Explain async and await in C#. The async and await are used in C# for asynchronous programming, allowing non-blocking execution. An async method performs work on a separate thread without blocking the main thread, and await is used to indicate where asynchronous operations pause and resume. Q 6. Explain the map() function in Python. The map() function in Python applies a given function to each item of an iterable (like a list) and returns a map object. For example, map(lambda x: x*2, [1, 2, 3]) results in [2, 4, 6]. Q 7. How is inheritance handled in JavaScript? JavaScript uses prototype-based inheritance, meaning objects inherit directly from other objects rather than classes. ES6 introduced classes syntactically, but they are still prototype- based. Q 8. What is a virtual function in C++? A virtual function in C++ is a function in a base class marked with the virtual keyword. This allows derived classes to override the function, enabling polymorphism. The actual function called depends on the object type.

11. Q 9. What is the final keyword in Java? In Java, the final keyword can be used with variables, methods, and classes. A final variable cannot be reassigned, a final method cannot be overridden, and a final class cannot be subclassed. Q 10. Explain the concept of closures in JavaScript. A closure in JavaScript is a function that retains access to its outer scope variables even after the outer function has completed execution. For example: function outer() { let count = 0; return function inner() { return ++count; }; } Q 11. What is the difference between ArrayList and LinkedList in Java? ArrayList is backed by a dynamic array, whereas a doubly linked list backs LinkedList. ArrayList offers fast access with slower insertions/removals, while LinkedList offers fast insertions/removals with slower access. Q 12. Explain the var, let, and const keywords in JavaScript. In JavaScript, var is function-scoped, while let and const are block-scoped. Let allows reassignment, but const does not. Q 13. How does C++ handle multiple inheritance? C++ supports multiple inheritance, allowing a class to inherit from more than one base class. This can lead to ambiguity, which can be resolved using virtual inheritance to avoid the "diamond problem." Q 14. What is the difference between __str__ and __repr__ in Python?

12. In Python, __str__ returns a readable string for end users, while __repr__ provides a developer- oriented representation of the object, often used for debugging. Q 15. What is LINQ in C#? LINQ (Language Integrated Query) is a set of methods in C# for querying collections. It provides the syntax for querying collections, databases, and XML data using lambda expressions. Q 16. How are private variables accessed in C++? Private variables in C++ are accessible only within the class that declares them. To access private variables, you typically use public getter and setter functions. Q 17. Explain __init__ and self in Python classes. In Python, __init__ is a constructor method called when an object is instantiated. self represents the instance of the class and is used to access class variables and methods. Q 18. What is const correctness in C++? The const correctness in C++ ensures that variables or parameters marked as const are not modified. It helps prevent accidental changes to values within functions and supports safer code. Q 19. What is the difference between abstract and sealed in C#? An abstract class in C# cannot be instantiated directly and is meant to be subclassed, with or without abstract methods. A sealed class cannot be inherited, making it a final implementation. Q 20. Explain async programming in JavaScript. JavaScript is single-threaded, so async programming allows non-blocking operations, using promises or async/await syntax to handle delayed operations like I/O without freezing the main thread.

13. Top 20 Google Interview Coding Questions for Practise Here, we provide some of the most important coding questions that you can practice for your job interview: Q 1. How do you reverse a linked list? Q 2. How would you detect a cycle in a linked list? Q 3. Write a function to check if a given string is a palindrome. Q 4. How do you find the intersection of two arrays? Q 5. How would you merge two sorted arrays? Q 6. Create a function that finds the largest sum of a subarray (Kadane's algorithm). Q 7. How do you determine the longest substring without repeated characters? Q 8. How would you assess whether a binary tree is balanced? Q 9. How do you determine the lowest common ancestor in a binary tree? Q 10. Create a function that checks if two strings are anagrams. Q 11. How would you get duplicates out of a sorted linked list? Q 12. Write a function that rotates a matrix by 90 degrees. Q 13. How do you determine the kth greatest element in an array? Q 14. How would you create a queue with two stacks? Q 15. Create a function that finds the first non-repeating character in a string. Q 16. How do you check if two binary trees are identical? Q 17. How would you implement depth-first search (DFS) in a graph? Q 18. Write a function to find the missing number in an array of consecutive numbers.

14. Q 19. would you check if a binary tree is a valid binary search tree (BST)? Q 20. How do you find the longest common prefix among an array of strings? System Design Interview Questions at Google Interview Let's go through some system-design interview questions: Q 1. Design a URL Shortener (like Bit.ly) A URL shortener takes long URLs and generates a shorter, unique version for easy sharing. Key considerations include how to handle millions of URL requests, ensuring unique shortened URLs, implementing a hashing function for unique mappings, managing high availability, and choosing the right database for quick retrieval. Q 2. Design a Web Crawler A web crawler is essential for indexing content across websites for search engines. Discuss how to handle large volumes of web data, prioritize crawling based on freshness and relevance, handle URL deduplication, and ensure distributed crawling to balance load across servers. You may also mention approaches to managing rate-limiting, politeness policies, and handling errors like 404 pages. Q 3. Design Google Drive or Dropbox This involves building a system to upload, store, sync, and retrieve files across devices. Key points include file chunking for upload efficiency, metadata management, data consistency across devices, redundancy for data recovery, and handling concurrency when multiple users update files simultaneously. Q 4. Design a Rate Limiter A rate limiter restricts the number of requests a user can make in a given period to prevent abuse. Key considerations include different algorithms like token buckets, fixed windows, and

15. sliding windows for rate-limiting, as well as storing data in memory or a fast-access cache for real-time decision-making. Consider scalability and how to handle distributed instances. Q 5. Design a Chat System (like WhatsApp) A chat system must support real-time messaging, user presence updates, and message history. Key points include how to manage user authentication, implement a message queue for real-time delivery, handle offline messages, ensure message ordering, and choose a suitable database for high-volume storage. Q 6. Design a Search Autocomplete System This involves predicting user queries as they type in a search bar. Discuss using Trie data structures for fast prefix searches, caching frequently typed queries for efficiency, ranking results based on popularity or personalization, and how to handle updates to the dataset for new trending queries. Q 7. Design a Notification System A notification system sends messages to users across different devices. Consider notification types (email, SMS, in-app), ensuring timely delivery, scheduling for specific times or events, handling retries for undelivered messages and user preferences, and using a queuing system to balance load during peak times. Q 8. Design a Content Delivery Network (CDN) A CDN distributes content across multiple locations so that users can access it faster globally. Discuss storing content in geographically distributed servers, caching strategies, load balancing across servers, and managing cache invalidation when content updates. Also, network latency and redundancy should be considered for reliability. Q 9. Design a Ride-Sharing System (like Uber) This involves matching drivers and passengers in real time. Key points include location tracking for real-time positioning, a matching algorithm for quick pairing, handling surge

16. pricing during peak hours, managing trip history, and ensuring data consistency between drivers and riders. Consider scalability for handling high user loads. Q 10. Design a News Feed System (like Facebook) A news feed delivers personalized content to users based on their activity and interests. Discuss ranking algorithms for relevance, how to manage a large number of updates in real- time, caching strategies for frequently viewed posts, and handling privacy settings. Additionally, consider ways to optimize the system for responsiveness and scalability. Google Cloud Interview Questions Q 1. What is Google Cloud Platform (GCP), and what services does it offer? Google Cloud Platform (GCP) is a suite of cloud services for computing, storage, data analytics, and machine learning. It offers services like Compute Engine, App Engine, BigQuery, Cloud Storage, and more. Q 2. Explain the differences between Google Cloud Storage classes. Google Cloud Storage offers different classes based on access frequency: Standard (frequent access), Nearline (less than once a month), Coldline (rarely accessed), and Archive (long-term storage). Q 3. What are the different types of virtual machines in Google Cloud? Google Cloud provides various VM types, including N1 Standard for general use, N2 for better performance, and specialized VMs like Compute-Optimized, Memory-Optimized, and Preemptible VMs for specific workloads. Q 4. How does Google Cloud Networking work?

17. Google Cloud Networking includes services like VPC for isolated networks, Cloud Load Balancing for traffic distribution, and Cloud CDN for content delivery with low latency globally. Q 5. What is Kubernetes Engine (GKE), and how does it work? Google Kubernetes Engine (GKE) is a managed service for deploying and managing containerized applications using Kubernetes, providing automated updates, scaling, and integration with other GCP services. Q 6. How does Google Cloud Identity and Access Management (IAM) work? Google Cloud IAM allows administrators to manage permissions for users, groups, and service accounts, assigning roles to grant access to specific GCP resources securely. Q 7. What is BigQuery, and how does it work? BigQuery is a fully managed, serverless data warehouse for fast SQL queries on large datasets, offering scalability and real-time analytics with minimal management. Q 8. What is Google Cloud Pub/Sub, and when would you use it? Google Cloud Pub/Sub is a messaging service for event-driven architectures used for asynchronous communication, real-time event processing, and decoupling services in distributed systems. Q 9. What is Google Cloud Spanner, and how is it different from traditional relational databases? Cloud Spanner is a globally distributed, scalable relational database offering ACID transactions, horizontal scaling, and strong consistency, unlike traditional databases that are limited in scalability. Q 10. How would you design a highly available and scalable architecture on Google Cloud?

18. To design a highly available and scalable system, use managed services, auto-scaling, multi- region resources, load balancing, and data replication to ensure performance and fault tolerance. Google Software Engineer Interview Questions Q 1. What is your approach to solving a coding problem? Understand the problem, break it into smaller parts, choose the right data structure/algorithm, write code, and then test and optimize it. Q 2. How do you optimize your code for better performance? time complexity, and reduce Use efficient algorithms and data structures, minimize unnecessary computations. Q 3. What is the difference between an array and a linked list? Arrays are fixed-size and allow fast access by index, while linked lists are dynamic and allow fast insertion/deletion but slower access. Q 4. What is a hash table, and how does it work? A hash table stores data in key-value pairs using a hash function to access values by their keys quickly. Q 5. What is dynamic programming? Dynamic programming solves problems by breaking them into overlapping subproblems and storing results to avoid redundant calculations. Q 6. What is the difference between a stack and a queue? A stack follows LIFO (Last In, First Out), and a queue follows FIFO (First In, First Out). Q 7. Explain object-oriented programming (OOP).

19. Object-Oriented Programming is a programming style based on objects, which encapsulate data and methods. Key principles include encapsulation, inheritance, polymorphism, and abstraction. Q 8. What is the time complexity of searching in a binary search tree (BST)? O(log n) for a balanced tree, but O(n) in the worst case for an unbalanced tree. Q 9. How do you handle debugging in your code? Use print statements, a debugger, or break the problem down to identify issues and fix them step-by-step. Q 10. How would you handle multiple tasks with tight deadlines? Prioritize tasks based on urgency, break them into smaller tasks, and focus on completing critical ones first. Q 11. What is a queue, and how is it used? A queue in a data structure is a data structure that follows FIFO and is used in scenarios like task scheduling or handling requests on a server. Q 12. What is the difference between deep copy and shallow copy? A shallow copy copies references to objects, while a deep copy duplicates the entire object, including nested objects. Q 13. What is a binary search? Binary search is a search algorithm that repeatedly divides a sorted list in half to find a target value with O(log n) time complexity. Q 14. What is recursion?

20. Recursion in C is when a function calls itself to solve smaller instances of a problem, often with a base case to stop the recursion. Q 15. What is the difference between a process and a thread? A process is an independent program in execution, while a thread is a smaller unit of a process that can run concurrently with other threads. Q 16. What is the importance of Big-O notation? Big-O notation helps to measure the efficiency of an algorithm, indicating its time and space complexity as the input size grows. Q 17. Explain the concept of inheritance in OOP. Inheritance in OOPs allows a class to inherit properties and methods from another class, promoting code reuse. Q 18. What is the difference between SQL and NoSQL databases? SQL databases are relational and use structured query language, while NoSQL databases are non-relational and handle unstructured or semi-structured data. Q 19. What is a race condition? A race condition occurs when two threads access shared resources simultaneously, causing unpredictable results. Q 20. How do you ensure code quality? Ensure code quality through writing unit tests and code reviews, adhering to coding standards, and using tools like linters to catch errors early. Google Interview Questions for Experienced Professionals

21. Q 1. What are the differences between a stack and a queue, and where would you use each? A stack follows the Last In, First Out (LIFO) principle, and a queue follows the First In, First Out (FIFO). Stacks are used in recursion and undo functionality, while queues are used for task scheduling and real-time systems. Q 2. How would you find the intersection of two arrays? You can use a hash set to store one array's elements and check for matches with the other array. Alternatively, sorting both arrays and using a two-pointer technique is another approach. Q 3. Explain the concept of a binary search tree and its use cases. A binary search tree (BST) is a tree where each node's left child is smaller and the right child is larger. It supports efficient searching, insertion, and deletion in O(log n) time and is used in search operations and range queries. Q 4. How would you implement an LRU (Least Recently Used) cache? An LRU cache can be implemented using a hash map and a doubly linked list. The hash map allows O(1) access to items, while the doubly linked list maintains the order of use for eviction. Q 5. What is dynamic programming? Can you give a real-world problem that requires this approach? Dynamic programming solves problems by breaking them down into overlapping subproblems and storing solutions. The Fibonacci sequence is a classic example where DP optimizes repeated calculations. Q 6. Design a URL shortening service (like bit.ly). This involves creating a system that maps long URLs to short ones using unique identifiers. It requires efficient URL mapping, redirection handling, and scalability.

22. Q 7. How would you design a scalable notification system? A scalable notification system uses message queues (like Kafka) to handle high volumes of notifications asynchronously and ensures real-time delivery using push notifications for mobile apps. Q 8. Explain the differences between a relational database and a NoSQL database. Relational databases use structured tables with a fixed schema, supporting ACID transactions. NoSQL databases are flexible, handle unstructured data, and focus on scalability and availability. Q 9. How would you find the shortest path in a weighted graph? Dijkstra’s algorithm can be used for graphs with non-negative weights, while Bellman-Ford handles negative weights. Both algorithms find the shortest path efficiently. Q 10. What is the difference between a process and a thread? A process is a standalone program with its own memory, while a thread is a smaller unit of execution within a process that shares the process's memory space. Q 11. Design a file storage system. A file storage system must handle file uploads, retrieval, and metadata management while ensuring scalability, redundancy, and data consistency across multiple storage nodes. Q 12. How would you implement an autocomplete feature for a search engine? Implementing autocomplete can involve using a trie or prefix tree, allowing efficient retrieval of suggestions based on user input. Q 13. What are the trade-offs between using a relational and a NoSQL database?

23. Relational databases are ideal for structured data and complex queries, supporting ACID properties. NoSQL databases offer better scalability and flexibility but typically sacrifice consistency for availability. Q 14. Explain the CAP theorem and its importance in distributed systems. The CAP theorem states that a distributed system can guarantee at most two of three properties: Consistency, Availability, and Partition Tolerance. It highlights trade-offs when designing distributed systems. Q 15. How would you implement a multithreaded program that computes the sum of a large array? Use threads to split the array into smaller parts, then compute each part in parallel, combining the results at the end, ensuring proper synchronization to avoid data races. Q 16. Design a messaging system like WhatsApp or Slack. A messaging system requires handling real-time communication, message delivery, storage, and ensuring scalability with efficient use of databases and message queues. Q 17. How would you handle a situation where a distributed system loses data? Use data replication, redundancy, and eventual consistency to handle failures and ensure data recovery in case of a loss. Q 18. What is a deadlock, and how can you prevent it in a multi- threaded application? Deadlock occurs when two or more threads are waiting indefinitely for each other to release resources. Prevent it by using lock ordering, timeouts, or deadlock detection techniques. Q 19. Design an e-commerce checkout system.

24. An e-commerce checkout system must manage inventory, handle transactions, and integrate payment gateways while ensuring consistency and scalability. Q 20. Explain the difference between synchronous and asynchronous programming. Synchronous programming blocks the execution until a task is completed, while asynchronous programming allows tasks to run concurrently, improving system responsiveness and resource utilization. Conclusion  In conclusion, mastering Google Interview Questions is key to succeeding in their rigorous interview process. By practicing common technical and system design questions, candidates can improve their problem-solving skills. Proper preparation for Google Interview Questions increases the chances of standing out and securing a position at the company.