Ozone Media Interview Questions and Answers

Find the first non-repeating character in a string.

• Create a hash table to store the frequency of each character in the string.

• Iterate through the string and check the frequency of each character.

• Return the first character with a frequency of 1.

Connection pooling is a technique of reusing database connections to improve performance.

• Connection pooling helps to reduce the overhead of creating and destroying database connections.

• It maintains a pool of connections that can be reused by multiple clients.

• Connection pooling is commonly used in web applications to handle multiple requests simultaneously.

• It can be configured with parameters like maximum number of conn...read more

A singleton class in PHP is a class that can only be instantiated once.

• Create a private constructor to prevent direct instantiation

• Create a private static variable to hold the instance of the class

• Create a public static method to get the instance of the class

• Ensure that the public static method always returns the same instance

To connect to MySQL database using PHP, create a Connection class.

• Use mysqli_connect() function to establish a connection

• Pass the database credentials as parameters to the function

• Create a constructor method to initialize the connection

• Create a query method to execute SQL queries

• Close the connection using mysqli_close() method

There are three types of errors in PHP: syntax errors, runtime errors, and logical errors.

• Syntax errors occur when the code is not written correctly, such as missing semicolons or parentheses.

• Runtime errors occur during the execution of the code, such as trying to access an undefined variable.

• Logical errors occur when the code runs without errors, but produces unexpected results, such as a miscalculation in a formula.

Session in PHP allows to store user data on the server for later use.

• Session starts when a user logs in and ends when the user logs out or the session expires.

• Session data is stored on the server and identified by a unique session ID.

• Session variables can be set and accessed using the $_SESSION superglobal array.

• Session can be destroyed using the session_destroy() function.

• Session can be used to store user-specific dat...read more

Find missing element in an array of elements from 0 to n-1

• Calculate sum of all elements in array and subtract from sum of n natural numbers

• Use XOR operation on all elements and n natural numbers

• Sort the array and find the missing element

Probability of a horse going out of a chessboard in 'n' steps.

• The total number of possible moves for a horse is 8.

• The probability of going out of the board depends on the position of the horse.

• For example, if the horse is at a corner, the probability of going out of the board is higher.

• The probability can be calculated using combinatorics and geometry.

Algorithms for manipulating arrays and strings in coding

• Use sorting algorithms like quicksort and mergesort for arrays

• Use string manipulation functions like substring and replace for strings

• Use dynamic programming for optimizing solutions to array and string problems

Designing a large scale Ad Server

• Use distributed systems for scalability

• Implement caching for faster ad delivery

• Ensure high availability and fault tolerance

• Use real-time bidding for efficient ad placement

• Implement fraud detection mechanisms

• Ensure compliance with privacy regulations

Maximum sub sequence sum in an array

• Use Kadane's algorithm

• Initialize max_so_far and max_ending_here to 0

• Iterate through the array and update max_ending_here and max_so_far

• Return max_so_far

Endianness refers to the byte order of a system. It determines how multi-byte data types are stored in memory.

• Little-endian systems store the least significant byte first, while big-endian systems store the most significant byte first.

• Endianness can affect the way data is transmitted between systems.

• To determine the endianness of a system, you can use the byte order mark (BOM) or write a test program that checks the by...read more

Sort an array of 0's and 1's only.

• Use two pointers, one at the beginning and one at the end of the array.

• Swap 0's from the beginning with 1's from the end until the pointers meet.

• Alternatively, use a counting sort algorithm to count the number of 0's and 1's and then reconstruct the array.

Heaps are data structures used to efficiently find the maximum or minimum element in a collection.

• Max heap: parent nodes are always greater than or equal to child nodes

• Min heap: parent nodes are always smaller than or equal to child nodes

• Heaps are commonly used in priority queues and sorting algorithms

• Heap operations include insert, delete, and extract max/min

• Example: An array [3, 8, 2, 5, 1, 4, 6] can be represented a

Find 3 numbers in an array where a+b=c.

• Loop through the array and check for all possible combinations of a and b.

• Use a hash table to store the values of a and b, and check if c is present in the hash table.

• Sort the array and use two pointers to find a and b, and then check if their sum equals c.

I prefer Python because of its simplicity, readability, and extensive libraries.

• Python is known for its simplicity and readability, making it easier to write and understand code.

• Python has a large number of libraries and frameworks that can be used to quickly develop applications.

• Python's syntax is clean and concise, allowing for faster development and easier maintenance.

• Python is widely used in various domains such as...read more

I want to work with Pubmatic because of their innovative technology solutions and strong reputation in the industry.

• Pubmatic is known for their cutting-edge technology solutions in the digital advertising space

• I admire Pubmatic's strong reputation and track record in the industry

• I believe working at Pubmatic will provide me with valuable learning opportunities and career growth

I am an avid traveler and have visited over 20 countries

• I love experiencing new cultures and trying new foods

• I have backpacked through Europe and Asia

• I have volunteered in orphanages in Cambodia and Nepal

Mobile advertising platform

• Adtech

• Mobile marketing

• App monetization