80+ Interview Questions and Answers

Write a select statement to retrieve work of all users who belong to my team.

• Join USERS and WORK tables on user_id

• Join MANAGERS and USERS tables on team

• Filter by manager_id

Multiple data structures are used to print nodes in a specific order. One data structure cannot be used alone.

• The given order suggests a depth-first search traversal of a tree-like structure.

• A stack can be used to keep track of the nodes to be visited.

• A queue can be used to store the children of a node in the order they are visited.

• An array can be used to store the nodes in the required order.

• A linked list can be used to connect the nodes in the required order.

• Using just one ...read more

Designing Google Suggest system

• I would start by analyzing user search patterns and frequently searched keywords

• Then, I would create a database of these keywords and their associated search results

• I would use indexing services to quickly retrieve relevant results for each keyword

• I would also implement machine learning algorithms to improve the accuracy of suggestions over time

Find largest pen using minimum comparisons with tops.

• Divide pens into two groups and compare largest pen from each group with largest top.

• Repeat the process with the group containing the largest pen until only one pen is left.

• The remaining pen is the largest pen.

• Total number of comparisons required is 2n-3.

Check if a number is a power of 2 and odd.

• To check if a number is a power of 2, use bitwise AND operator with the number and its predecessor. If the result is 0, it is a power of 2.

• To check if a number is odd, use modulus operator with 2. If the result is 1, it is odd.

• Example code in Python:

• def is_power_of_two(num):

• return num & (num - 1) == 0

• def is_odd(num):

• return num % 2 == 1

Algorithm to find 2 numbers in an array whose sum is equal to a target integer

• Use a hash table to store the difference between target and each element in the array

• Iterate through the array and check if the current element exists in the hash table

• Return the pair of elements that sum up to the target integer

Given n dice with 'a' sides and sum b, return no. of ways to obtain b. Optimize time and space complexity.

• Use dynamic programming to reduce time complexity

• Create a 2D array to store the number of ways to obtain each sum for each number of dice

• Use rolling arrays to optimize space complexity

• Example: n=2, a=6, b=7 -> 6 ways to obtain sum 7

• Example: n=3, a=4, b=8 -> 21 ways to obtain sum 8

Hashtable is faster for finding an item than a sorted list.

• Hashtable has constant time complexity O(1) for finding an item.

• Sorted list has logarithmic time complexity O(log n) for finding an item.

• Hashtable uses hashing to directly access the item's location.

• Sorted list requires binary search to find the item's location.

• Hashtable is ideal for large datasets with frequent lookups.

• Sorted list is ideal for datasets that require frequent insertions and deletions.

Sort 128 GB data on 2 machines with 64 GB RAM each. Extend to 1000 machines.

• Use external sorting algorithm like merge sort or quick sort

• Divide data into smaller chunks and sort them individually

• Merge sorted chunks using additional RAM

• For 1000 machines, use distributed sorting algorithms like MapReduce or Hadoop

• Ensure data consistency and fault tolerance in distributed sorting

Reviewing 30 million ads from 42 languages in Google AdWords and rejecting non-compliant ads requires a systematic approach.

• Create a set of specific rules and guidelines for ad compliance

• Use automated tools to filter out ads that violate the rules

• Assign a team of reviewers to manually check the remaining ads

• Ensure that the reviewers are fluent in the languages of the ads they are reviewing

• Regularly update the rules and guidelines to keep up with changes in the industry

• Provide...read more

Use a script to automate the process of changing phone number format in 1000 static html pages.

• Create a script using a programming language like Python or JavaScript.

• Use regular expressions to identify phone numbers in the HTML pages.

• Use string manipulation functions to change the format of the phone numbers.

• Test the script on a small sample of HTML pages before running it on all 1000 pages.

• Make sure to backup the original HTML pages before making any changes.

JSON and XML are the most popular data interchange formats when using APIs.

• JSON (JavaScript Object Notation) is a lightweight format that is easy to read and write. It is widely used in web APIs.

• XML (Extensible Markup Language) is a more complex format that is also widely used in web APIs.

• Other formats include CSV (Comma Separated Values), YAML (YAML Ain't Markup Language), and Protocol Buffers.

My strength lies in my problem-solving skills and ability to work well in a team. My long term goal is to become a lead developer and contribute to innovative projects.

• Strong problem-solving skills

• Effective team player

• Long term goal of becoming a lead developer

• Contribute to innovative projects

By introducing new menu items, optimizing pricing strategy, and improving the overall dining experience.

• Conduct a survey to understand the preferences of employees

• Introduce healthy and affordable meal options

• Offer discounts for bulk orders or loyalty programs

• Partner with local vendors to source fresh ingredients

• Improve the ambiance and seating arrangements

• Implement online ordering and delivery services

Linked List is the best-suited data structure for chain type data.

• Linked List is a dynamic data structure that can grow or shrink during runtime.

• It allows efficient insertion and deletion operations.

• Each node in the linked list contains a reference to the next node.

• Examples of chain type data include a list of songs in a playlist or a list of tasks in a to-do list.

Popular APIs for Social Commerce services

• Facebook Graph API for social media integration

• Instagram API for photo sharing and tagging

• Twitter API for real-time updates and customer engagement

• Pinterest API for product discovery and sharing

• Google Maps API for location-based services

• PayPal API for secure payment processing

Java is platform independent due to its bytecode and JVM implementation.

• Java code is compiled into bytecode, which can run on any platform with a Java Virtual Machine (JVM)

• JVM acts as an interpreter, translating bytecode into machine code specific to the underlying platform

• This allows Java programs to be written once and run anywhere, without the need for recompilation

Static binding is resolved at compile time, while dynamic binding is resolved at runtime.

• Static binding is also known as early binding, where the method call is resolved at compile time based on the type of the object.

• Dynamic binding is also known as late binding, where the method call is resolved at runtime based on the actual type of the object.

• Example of static binding: method overloading.

• Example of dynamic binding: method overriding.

The data can be represented in memory using a combination of data structures like objects and arrays.

• Use objects to represent the input, output, server, and person data

• Use arrays to store multiple values like filenames or hostnames

• Use key-value pairs to store specific information like age or type

Lambda expression in JAVA is a concise way to represent a method implementation using a functional interface.

• Lambda expressions are used to provide a more concise way to implement functional interfaces in JAVA.

• They are similar to anonymous classes but with less boilerplate code.

• Lambda expressions can be used to pass behavior as an argument to a method.

• Syntax: (parameters) -> expression or (parameters) -> { statements; }

• Example: (int a, int b) -> a + b

Yes, many companies use Applicant Tracking Systems for initial shortlisting.

• Many companies use ATS to manage and filter large volumes of applications

• ATS can automatically screen resumes based on keywords and qualifications

• Some examples of popular ATS include Greenhouse, Lever, and Workday

I am proficient in programming languages such as Java, Python, C++, and JavaScript.

• Java

• Python

• C++

• JavaScript

The code will iterate over the characters in 'pythonlife' and print each character until it reaches 'l', then it will stop.

• The code uses a for loop to iterate over each character in the string 'pythonlife'.

• When the character 'l' is encountered, the loop will break and stop iterating.

• The loop will print each character until 'l' is reached, so the output will be 'python'.

Implement a tokenizer interface to parse a configuration stream into a data structure.

• Create a class that implements the Tokenizer interface

• Use the hasNext method to check if there are more tokens to parse

• Use the nextToken method to retrieve the next token from the stream

• Store the tokens in a data structure such as a list or map

JVM is a virtual machine that enables a computer to run Java programs.

• JVM is platform-independent and converts Java bytecode into machine code.

• It consists of class loader, runtime data areas, execution engine, and native method interface.

• JVM manages memory, garbage collection, and exception handling.

• Examples of JVM implementations include Oracle HotSpot, OpenJ9, and GraalVM.

The code will print numbers from 0 to 8 in separate lines.

• The 'range' function generates a sequence of numbers from 0 to 8 (9 is exclusive).

• The 'for' loop iterates through each number in the sequence and prints it.

Use a heap data structure to find the 4th largest data in an array.

• Create a max heap from the array

• Pop the top element from the heap 3 times to get the 4th largest element

• Return the 4th largest element

Different cases used for software testing include functional, performance, security, usability, and compatibility testing.

• Functional testing ensures that the software meets the specified requirements

• Performance testing checks the software's speed, scalability, and stability under different loads

• Security testing identifies vulnerabilities and ensures data protection

• Usability testing evaluates the software's user-friendliness

• Compatibility testing checks the software's compatibi...read more

Google is better than Facebook due to its focus on search and information retrieval.

• Google's primary focus is on search and information retrieval, while Facebook is more focused on social networking.

• Google's search algorithm is more advanced and accurate compared to Facebook's search functionality.

• Google offers a wide range of services beyond social networking, such as Google Maps, Gmail, and Google Drive.

• Google has a larger market share and is considered the go-to search eng...read more

DSA stands for Data Structures and Algorithms. It is essential for efficient problem-solving in software development.

• DSA helps in organizing and managing data effectively

• It improves the efficiency and performance of algorithms

• Common data structures include arrays, linked lists, trees, graphs

• Common algorithms include sorting, searching, and dynamic programming

Remove unnecessary spaces in a given string.

• Use the trim() method to remove leading and trailing spaces.

• Use replace() method with regex to remove multiple spaces between words.

• Example: ' Hello World ' -> 'Hello World'

Optimize a^b calculation using bitwise operations

• Use bitwise operations like left shift and AND to optimize exponentiation

• Avoid using traditional multiplication for each iteration

• Example: Optimized power function in C++ - int power(int a, int b) { int result = 1; while (b > 0) { if (b & 1) result *= a; a *= a; b >>= 1; } return result; }

Types of inheritances include single, multiple, multilevel, hierarchical, hybrid, and multipath.

• Single inheritance: a class inherits from only one base class.

• Multiple inheritance: a class inherits from more than one base class.

• Multilevel inheritance: a class inherits from a class which in turn inherits from another class.

• Hierarchical inheritance: multiple classes inherit from a single base class.

• Hybrid inheritance: combination of multiple and multilevel inheritance.

• Multipath ...read more

A program that breaks another program into smaller parts or components.

• Use functions or modules to break down the main program into smaller, more manageable parts

• Consider using object-oriented programming principles to encapsulate related functionality

• Utilize comments and documentation to explain the purpose and functionality of each part

Windows functions in SQL are built-in functions that perform calculations across a set of rows and return a single value.

• Windows functions are used to perform calculations on a specific subset of rows in a result set.

• They are often used with the OVER clause to define the window of rows over which the function operates.

• Examples of windows functions include ROW_NUMBER(), RANK(), and SUM().

Splitting search query involves breaking it down into individual keywords or phrases for more accurate results.

• Identify key words or phrases in the search query

• Use delimiters like spaces or commas to separate the query into individual components

• Consider using regular expressions for more complex splitting requirements

My goal is to continuously improve my technical skills, contribute to innovative projects, and advance in my career as a software developer.

• Continuous learning and improvement in technical skills

• Contributing to innovative projects

• Advancing in my career as a software developer

Use a priority queue to find top k nodes with highest value in a tree

• Traverse the tree and store nodes in a priority queue based on their values

• Pop k nodes from the priority queue to get the top k nodes with highest value

A for loop is used to iterate over a sequence of elements for a specified number of times.

• Initialize a counter variable before the loop

• Set the condition for the loop to continue based on the counter variable

• Update the counter variable after each iteration

• Example: for(int i = 0; i < 5; i++) { // code block }

C++ and Java have different strengths and weaknesses, it's not accurate to say one is 'bad' compared to the other.

• C++ is closer to the hardware and allows for more low-level programming, while Java is more platform-independent and easier to learn.

• C++ gives more control over memory management, but this can lead to more bugs if not handled properly.

• Java has automatic garbage collection, making memory management easier for developers.

• C++ is often used for system programming and ...read more

C++ is a programming language used for developing software applications.

• C++ is a high-level programming language known for its performance and flexibility.

• It is commonly used for developing system software, game engines, and applications that require high performance.

• C++ supports object-oriented programming, generic programming, and low-level memory manipulation.

• Examples of software developed using C++ include operating systems like Windows, game engines like Unreal Engine, a...read more

Java is a popular programming language used for developing a wide range of applications.

• Java is platform-independent, meaning it can run on any device with a Java Virtual Machine (JVM)

• It is used for developing web applications, mobile apps, desktop applications, and enterprise software

• Java is known for its security features and scalability

• Examples of Java-based applications include Android apps, online banking systems, and e-commerce websites

The main goal of a Software Developer is to design, develop, and maintain software applications to meet the needs of users.

• Designing software applications based on user requirements

• Developing code to implement the design

• Testing and debugging software to ensure functionality

• Maintaining and updating software as needed

• Collaborating with team members to achieve project goals

Calculate the average of each subtree on a node in an N-arry tree.

• Traverse the tree using depth-first search (DFS)

• Maintain a sum and count for each subtree while traversing

• Calculate the average by dividing the sum by the count for each subtree

I typically code for 6-8 hours daily, with breaks in between for rest and refreshment.

• I code for 6-8 hours daily to ensure productivity and progress on projects.

• I take breaks in between coding sessions to rest my mind and prevent burnout.

• I prioritize quality over quantity, focusing on writing clean and efficient code.

• I enjoy coding and often spend extra time outside of work hours on personal projects or learning new technologies.

I have over 5 years of experience in software development, with a strong focus on web applications and database management.

• Developed web applications using HTML, CSS, JavaScript, and various frameworks like Angular and React

• Proficient in database management with SQL and NoSQL databases such as MySQL and MongoDB

• Experience in version control systems like Git for collaborative development

• Strong problem-solving skills and ability to work in a team environment

• Continuously learning...read more

Use two heaps to keep track of the numbers and find median efficiently.

• Use a max heap to store the smaller half of the numbers and a min heap to store the larger half.

• Keep the size of the two heaps balanced or with a difference of at most 1.

• If the total number of elements is odd, the median is the top element of the larger heap. If even, it's the average of the tops of both heaps.

MySQL is a full-featured relational database management system, while SQLite is a lightweight, serverless, self-contained database engine.

• MySQL is designed for larger applications with client-server architecture, while SQLite is suitable for smaller projects or embedded systems.

• MySQL supports multiple users and concurrent connections, while SQLite is limited to single-user access.

• MySQL has more advanced features like stored procedures, triggers, and views, while SQLite is sim...read more

Sorting an array of strings without using inbuilt methods

• Use a sorting algorithm like bubble sort, selection sort, or insertion sort

• Compare each element with the next one and swap if necessary

• Repeat the process until the array is sorted

Interfaces in Java are a way to achieve abstraction and multiple inheritance by defining a contract that classes must implement.

• Interfaces in Java are similar to classes but can only contain method signatures and constants, not method implementations.

• Classes can implement multiple interfaces, allowing them to inherit behavior from multiple sources.

• Interfaces are used to achieve abstraction and decouple the implementation from the interface, promoting flexibility and reusabili...read more

JavaScript is a programming language used for creating interactive web pages and web applications.

• JavaScript is a high-level, interpreted language.

• It is primarily used for client-side scripting.

• JavaScript can be embedded directly into HTML pages.

• It provides dynamic functionality and interactivity to websites.

• Common uses include form validation, DOM manipulation, and AJAX requests.

I will reallocate resources based on project priorities and team needs.

• Prioritize tasks based on project deadlines and importance

• Communicate with team members to understand their workload and availability

• Adjust resources as needed to ensure project success

• Example: If a critical project is falling behind schedule, I may reallocate resources from less urgent projects to meet the deadline

A linked list is a linear data structure where elements are stored in nodes that have a reference to the next node in the sequence.

• Consists of nodes connected by pointers

• Does not have a fixed size like arrays

• Allows for efficient insertion and deletion operations

• Example: Singly linked list, Doubly linked list

Multi-source BFS on an array of strings involves finding the shortest path from multiple starting points to a target point.

• Implement BFS algorithm to traverse the array of strings starting from multiple sources simultaneously.

• Maintain a queue of nodes to visit next, and keep track of visited nodes to avoid revisiting.

• Update the distance of each node from the sources as you traverse the array.

• Example: Given an array of strings representing a grid, find the shortest path from m...read more

Coding programs can vary in complexity depending on the requirements and functionalities needed.

• Complexity can be measured using Big O notation, which describes the worst-case scenario for time and space complexity.

• Factors affecting complexity include data structures used, algorithms implemented, and the size of input data.

• Examples of complex programs include machine learning algorithms, large-scale distributed systems, and real-time processing applications.

Find the maximum sum of a subarray within an array of strings.

• Iterate through the array and keep track of the maximum sum of subarrays.

• Use Kadane's algorithm to efficiently find the maximum sum subarray.

• Example: ['1', '2', '-3', '4', '5', '-6'] -> Maximum sum subarray is ['4', '5'].

Binary search is a fast search algorithm that finds the position of a target value within a sorted array.

• Ensure the array is sorted before performing binary search.

• Compare the target value with the middle element of the array.

• If the target value is less than the middle element, search the left half of the array. If it is greater, search the right half.

• Repeat the process until the target value is found or the subarray is empty.

A HashMap is a data structure that stores key-value pairs. To find all buddies in a HashMap, we need to iterate through the entries and compare values.

• Iterate through the entries of the HashMap

• Compare values to find buddies

• Store buddies in an array of strings

Trees are data structures used to store hierarchical data. They are commonly used in algorithms and problem-solving.

• Trees have a root node and branches that connect to other nodes.

• Common tree traversal methods include in-order, pre-order, and post-order.

• Examples of tree-based problems include finding the lowest common ancestor, balancing a binary search tree, and implementing a trie data structure.