Uber India Research And Development Interview Questions and Answers for Freshers

I am excited to join the company because of its reputation for innovation and commitment to employee growth.

• I am impressed by the company's track record of developing cutting-edge software solutions.

• I appreciate the company's focus on fostering a culture of learning and development.

• I am excited about the opportunity to work with a talented team of developers and contribute to the company's success.

• I believe that the co...read more

PreOrder traversal without recursion is done using a stack to simulate the function call stack.

• Create an empty stack and push the root node onto it.

• While the stack is not empty, pop a node from the stack and process it.

• Push the right child of the popped node onto the stack if it exists.

• Push the left child of the popped node onto the stack if it exists.

Yes

• Create an empty binary search tree (BST)

• Loop over the unsorted array

• For each element, insert it into the BST using the appropriate insertion logic

• Repeat until all elements are inserted

• The resulting BST will be built from the unsorted array

The question asks to find two elements 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 as you iterate through the array for efficient lookup.

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

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

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

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

• Examples: A DML trigger can be used to log changes made to a table, while a DDL trigger can be used to enforce certain rules when a table is alt

Yes, triggers can be used with select statements in SQL.

• Triggers are database objects that are automatically executed in response to certain events, such as insert, update, or delete operations.

• While triggers are commonly used with insert, update, and delete statements, they can also be used with select statements.

• Using triggers with select statements allows you to perform additional actions or validations before or af...read more

Indexing in MySQL improves query performance. There are several types of indexing in MySQL.

• Indexes are used to quickly locate data without scanning the entire table.

• Types of indexing in MySQL include B-tree, hash, full-text, and spatial indexes.

• B-tree indexes are the most common and suitable for most use cases.

• Hash indexes are used for exact match lookups.

• Full-text indexes are used for searching text-based data efficie...read more

Engines in MySQL are the underlying software components that handle storage, indexing, and querying of data.

• MySQL supports multiple storage engines, each with its own strengths and features.

• Some commonly used engines in MySQL are InnoDB, MyISAM, and Memory.

• InnoDB is the default engine in MySQL and provides support for transactions and foreign keys.

• MyISAM is known for its simplicity and speed but lacks transaction suppo...read more

Yes, a constructor can be private.

• A private constructor can only be accessed within the class itself.

• It is often used in singleton design pattern to restrict object creation.

• Private constructors are also useful for utility classes that only contain static methods.

Yes, I am comfortable traveling for work.

• I have experience traveling for work in my previous roles.

• I am adaptable and enjoy exploring new places.

• I am willing to travel for client meetings and conferences.

• I understand the importance of face-to-face interactions in sales.

• I am organized and can handle the logistics of travel efficiently.

Regex for email validation

• Start with a string of characters followed by @ symbol

• Followed by a string of characters and a period

• End with a string of characters with a length of 2-6 characters

• Allow for optional subdomains separated by periods

• Disallow special characters except for . and _ in username

Print prime numbers in a given range and optimize the solution.

• Use Sieve of Eratosthenes algorithm to generate prime numbers efficiently

• Start with a boolean array of size n+1, mark all as true

• Loop through the array and mark all multiples of each prime as false

• Print all the indexes that are still marked as true

Find angle between hour and minute hand in a clock given the time.

• Calculate the angle made by the hour hand with respect to 12 o'clock position

• Calculate the angle made by the minute hand with respect to 12 o'clock position

• Find the difference between the two angles and take the absolute value

• If the angle is greater than 180 degrees, subtract it from 360 degrees to get the smaller angle

To un-hash a string, use a reverse algorithm to convert the hash back to the original string.

• Create a reverse algorithm that takes the hash as input and outputs the original string

• Use the same logic as the hash function but in reverse order

• If the hash function used a specific algorithm, use the inverse of that algorithm to un-hash the string