ADRA Interview Questions and Answers

Return all root to leaf node paths in a binary tree with row, col and value.

• Traverse the binary tree recursively and keep track of the current path.

• When a leaf node is reached, add the path to the result array.

• Include row, col and value of each node in the path.

• Use an array of strings to store the paths.

To get max value from a stack in O(1), maintain a separate stack to keep track of maximum values.

• Create a separate stack to keep track of maximum values

• Push the maximum value onto the stack whenever a new maximum is encountered

• Pop the maximum value stack whenever the top element of the main stack is popped

• Return the top element of the maximum value stack to get the maximum value in O(1)

To get max element from a queue in O(1) time complexity

• Maintain a separate variable to keep track of the maximum element in the queue

• Update the maximum element variable whenever a new element is added or removed from the queue

• Return the maximum element variable when getMax() function is called

Find the Next Greatest Element to the right for each element in an array of strings.

• Iterate through the array from right to left

• Use a stack to keep track of elements

• Pop elements from stack until a greater element is found

• If no greater element is found, assign -1

• Return the result array

To remove unnecessary parenthesis from an expression, we need to apply a set of rules to identify and eliminate them.

• Identify and remove parenthesis around single variables or constants

• Identify and remove parenthesis around expressions with only one operator

• Identify and remove parenthesis around expressions with operators of equal precedence

• Identify and remove parenthesis around expressions with operators of different ...read more

Find the maximum product of three integers in an array.

• Sort the array in descending order.

• Check the product of the first three numbers and the product of the first and last two numbers.

• Return the maximum of the two products.

Find length of longest consecutive sub array forming an AP from given array of integers.

• Sort the array in ascending order

• Iterate through the array and find the longest consecutive sub array forming an AP

• Use a variable to keep track of the length of the current consecutive sub array forming an AP

• Use another variable to keep track of the length of the longest consecutive sub array forming an AP seen so far

Operating on images in parallel involves dividing the image into smaller parts and processing them simultaneously.

• Divide the image into smaller parts using techniques like tiling or splitting

• Use parallel processing techniques like multi-threading or GPU acceleration

• Combine the processed parts to form the final image

• Examples: image segmentation, object detection, image enhancement

Hardware engines support parallelism through multiple cores and threads.

• Hardware engines can have multiple cores and threads to execute tasks simultaneously.

• Parallelism can improve performance and efficiency in hardware-based tasks.

• Examples include GPUs, FPGAs, and ASICs that have parallel processing capabilities.

• Hardware parallelism can also be achieved through distributed computing and clustering.

• Programming language...read more

Modern OSes support parallelism through multi-core processors and threading.

• Modern OSes like Windows, macOS, and Linux support parallelism through multi-core processors and threading.

• Parallelism can be achieved through processes or threads.

• Parallelism can improve performance and efficiency of software.

• Examples of parallel programming frameworks include OpenMP and MPI.

Memory protection is a feature of an operating system that prevents unauthorized access to memory locations.

• Memory protection is achieved through the use of memory management units (MMUs) and virtual memory.

• MMUs map virtual addresses to physical addresses and enforce access permissions.

• Virtual memory allows the OS to allocate memory to processes in a way that isolates them from each other.

• Examples of memory protection ...read more

To speed up multiplication of small integers in an array, we can use bitwise operations and parallel processing.

• Use bitwise operations like shifting and ANDing to perform multiplication faster.

• Divide the array into smaller chunks and perform multiplication in parallel using multi-threading or SIMD instructions.

• Use lookup tables for frequently used values to avoid repeated calculations.

• Use compiler optimizations like lo...read more

Design a data structure for excel spreadsheet

• Use a 2D array to store cell values

• Implement formulas using a stack

• Include formatting options for cells

Insertion sort and quicksort are sorting algorithms used to sort arrays of data.

• Insertion sort: iterates through the array and inserts each element into its proper position.

• Quicksort: selects a pivot element and partitions the array into two sub-arrays, one with elements less than the pivot and one with elements greater than the pivot.

• Insertion sort is best for small arrays, while quicksort is best for large arrays.

• Bot...read more

Merge two sorted linked lists using recursion

• Create a recursive function that compares the first nodes of both lists

• Set the smaller node as the head of the merged list and call the function again with the next node of the smaller list

• Base case: if one list is empty, return the other list

• Return the merged list

Given an integer, determine which byte is zero.

• Convert the integer to a byte array using bitwise operations.

• Iterate through the byte array and check for a zero value.

• Return the index of the zero byte.

• Consider endianness when converting to byte array.

To check endianness, create a 4-byte integer with a known value and check the byte order.

• Create a 4-byte integer with a known value

• Check the value of the first byte to determine endianness

• If the first byte is the least significant, the machine is little endian

• If the first byte is the most significant, the machine is big endian

Static objects can be used to print something before main() execution.

• Static objects are initialized before main() execution

• They can be used to print something before main()

• Example: static int x = printf("Hello World!");

• Output: Hello World! will be printed before main() execution

Static variables are allocated memory in the data segment of the program's memory space.

• Static variables have a fixed memory location throughout the program's execution.

• They are initialized to zero by default.

• If initialized explicitly, they are stored in the data segment.

• Static variables can be accessed by any function in the program.

Finding space and time complexity of a recursive function.

• Space complexity is the amount of memory used by the function.

• Time complexity is the amount of time taken by the function to execute.

• Recursive functions have higher space complexity due to the call stack.

• Time complexity can be calculated using Big O notation.

• Examples of recursive functions include factorial and Fibonacci sequence.

Diamond hierarchy problem is a problem in object-oriented programming where a class inherits from multiple classes in a diamond-shaped hierarchy.

• Occurs when a class inherits from two classes that share a common base class

• Can lead to ambiguity in method calls and data members

• Solved using virtual inheritance or by using interfaces

A friend function is a non-member function that has access to the private and protected members of a class.

• Declared inside the class but defined outside the class scope

• Can access private and protected members of the class

• Not a member of the class but has access to its private members

• Used to allow external functions to access and modify private data of a class

• Can be declared as a friend in another class

atoi function converts a string to an integer in C.

• The function takes a string as input and returns an integer.

• Leading white spaces are ignored.

• If the string contains non-numeric characters, the function stops conversion and returns the converted value.

• The function returns 0 if the input string is not a valid integer.

• Example: atoi('123') returns 123.

A program to print star pattern

• Use nested loops to print the pattern

• The outer loop controls the number of rows

• The inner loop controls the number of stars to be printed in each row

• Use print() or println() function to print the stars

Run time polymorphism is the ability of a program to determine the object type at runtime and call the appropriate method.

• It is achieved through virtual functions and dynamic binding.

• Allows for more flexible and extensible code.

• Example: a base class Animal with virtual function makeSound() and derived classes Dog and Cat that override makeSound().

• At runtime, if an Animal pointer points to a Dog object, calling makeSoun

Right outer join is a type of join operation that returns all the rows from the right table and the matching rows from the left table.

• Right outer join is denoted by the RIGHT JOIN keyword in SQL.

• It is used to combine rows from two tables based on a related column.

• In the result set, unmatched rows from the right table will have NULL values for the columns of the left table.

• A real-world scenario for using a right outer j...read more

Refrential integrity ensures that relationships between tables in a database remain consistent.

• It is a database concept that ensures that foreign key values in one table match the primary key values in another table.

• It prevents orphaned records in a database.

• It maintains data consistency and accuracy.

• For example, if a customer record is deleted, all related orders for that customer should also be deleted.

• It is enforced...read more

Primary key uniquely identifies a record in a table, while Unique key ensures uniqueness of a column.

• Primary key can't have null values, Unique key can have one null value

• A table can have only one Primary key, but multiple Unique keys

• Primary key is automatically indexed, Unique key is not necessarily indexed

Triggers are database objects that are automatically executed in response to certain events.

• Triggers can be used to enforce business rules, audit changes, or replicate data.

• There are two types of triggers: DML triggers and DDL triggers.

• DML triggers are fired in response to DML statements (INSERT, UPDATE, DELETE).

• DDL triggers are fired in response to DDL statements (CREATE, ALTER, DROP).

Swapping two character variables without using third

• Use XOR operator to swap two variables without using third variable

• Assign the XOR of both variables to the first variable

• Assign the XOR of the first variable and second variable to the second variable

I have been actively involved in various extra curricular activities such as volunteering, sports, and leadership roles.

• Volunteered at local animal shelter every weekend

• Captain of the soccer team in high school

• Organized charity events for underprivileged children

I am a software developer with experience in Java and Python.

• Proficient in Java and Python programming languages

• Experience in developing web applications using Spring framework

• Familiarity with database management systems such as MySQL and MongoDB

I have achieved success in developing and implementing various software solutions.

• Developed a web application that increased user engagement by 30%

• Implemented a new feature that reduced system downtime by 50%

• Created a mobile app that received 4.5-star rating on app stores

• Led a team of developers to successfully complete a project within a tight deadline

I work on a variety of projects ranging from web development to mobile app development.

• Web development using HTML, CSS, JavaScript, and various frameworks such as React and Angular

• Mobile app development for iOS and Android using Swift, Kotlin, and React Native

• Database design and management using SQL and NoSQL databases such as MySQL and MongoDB

• API development and integration using REST and GraphQL

• Machine learning proje...read more

A hardworker puts in more effort, while a smartworker works efficiently and effectively.

• A hardworker may spend more time on a task, while a smartworker finds ways to complete it faster.

• A hardworker may rely on brute force, while a smartworker uses their skills and knowledge to solve problems.

• A hardworker may struggle with prioritization, while a smartworker knows how to focus on the most important tasks.

• A hardworker ma...read more

Zuckerberg is in news due to Facebook's handling of user data and misinformation.

• Facebook's role in the 2016 US Presidential election

• Cambridge Analytica scandal

• Testimony before US Congress

• Ongoing debate on social media regulation

I am a software developer with experience in Java and Python.

• I have a Bachelor's degree in Computer Science.

• I have worked on various projects involving web development and data analysis.

• I am proficient in Java and Python programming languages.

• I am a quick learner and enjoy working in a team environment.

My favorite project is the e-commerce website I developed for a local business.

• I enjoyed working on the front-end design and user experience.

• I implemented a secure payment gateway and order tracking system.

• The website increased the business's online sales by 50%.

• I received positive feedback from the client and their customers.

Inheritance is a mechanism in object-oriented programming where a new class is created by inheriting properties of an existing class.

• Inheritance allows code reuse and promotes code organization.

• The existing class is called the parent or superclass, and the new class is called the child or subclass.

• The child class inherits all the properties and methods of the parent class and can also add its own unique properties and ...read more

finally is a keyword used in try-catch block, finalize is a method in Object class, and final is a keyword used for declaring constants.

• finally is used to execute a block of code after try-catch block

• finalize is called by garbage collector before destroying an object

• final is used to declare a constant variable or to make a class uninheritable

Private keyword restricts access to member functions within the class while final keyword prevents overriding of functions.

• Private keyword is used to hide the implementation details of a class from the user.

• Final keyword is used to prevent the user from overriding a function in a subclass.

• Using private and final keywords together can ensure that the implementation details of a class are not modified by the user.

An interface defines a set of methods that a class must implement.

• An interface is declared using the 'interface' keyword.

• All methods in an interface are public and abstract by default.

• A class can implement multiple interfaces.

• Interfaces can also extend other interfaces.

• Example: public interface MyInterface { void myMethod(); }

Abstract class is a class with some implementation while Interface is a contract with no implementation.

• Abstract class can have constructors while Interface cannot

• Abstract class can have non-abstract methods while Interface cannot

• A class can implement multiple interfaces but can only inherit from one abstract class

• Abstract class is used when there is a need for common functionality among related classes while Interface...read more

Inheritance types in Java

• Java supports single and multiple inheritance through classes and interfaces respectively

• Single inheritance is when a class extends only one parent class

• Multiple inheritance is when a class implements multiple interfaces

• Java also supports hierarchical inheritance where multiple classes extend a single parent class

• Java does not support multiple inheritance through classes to avoid the diamond pr

Order of catch blocks in a try block in Java

• Specific catch blocks should come before general catch blocks

• If general catch block comes before specific catch block, it will result in a compile-time error

• If multiple catch blocks are present, only the first matching catch block will be executed

Garbage collection is an automatic memory management process that frees up memory occupied by objects that are no longer in use.

• Garbage collection is used in programming languages like Java, C#, and Python.

• It helps prevent memory leaks and reduces the risk of crashes due to memory exhaustion.

• Garbage collection works by identifying objects that are no longer in use and freeing up the memory they occupy.

• There are differe...read more

Code for connecting a Java application to a database

• Import the JDBC driver for the specific database

• Create a connection object using the DriverManager class

• Create a statement object to execute SQL queries

• Execute the query and retrieve the results

• Close the connection and release resources

JSON stands for JavaScript Object Notation, a lightweight data interchange format.

• JSON is used to transmit data between a server and a web application, as an alternative to XML.

• It is easy to read and write for humans and easy to parse and generate for machines.

• JSON is a text format that is completely language independent but uses conventions that are familiar to programmers of the C family of languages.

• Example: {"name"