ZAPR Media Labs AVP Interview Questions and Answers

Find pair of elements in an array whose sum is equal to a given number K.

• Iterate through the array and for each element, check if K minus the element exists in the array.

• Use a hash table to store the elements and their indices for faster lookup.

• If multiple pairs exist, return any one of them.

• If no pair exists, return null or an appropriate message.

Session is maintained using session affinity or sticky sessions.

• Session affinity ensures that a user's session is always directed to the same server.

• Load balancer uses a unique identifier to route requests to the same server.

• Sticky sessions can be implemented using cookies or URL rewriting.

• Session replication can also be used to maintain session data across multiple servers.

Singleton pattern ensures only one instance of a class is created and provides a global point of access to it.

• Create a private constructor to prevent direct instantiation of the class

• Create a private static instance of the class

• Create a public static method to access the instance

• Ensure thread safety by using synchronized keyword or static initialization block

• Examples: Logger, Configuration Manager, Database Connection

Explaining abstract class, interface and multiple inheritance in PHP.

• Abstract class is a class that cannot be instantiated and can have abstract methods.

• Interface is a collection of abstract methods and constants that can be implemented by a class.

• Multiple inheritance is not possible in PHP, but can be achieved using interfaces.

• Interfaces can be implemented by multiple classes, allowing for multiple inheritance-like be

Write a stored procedure from given tables and conditions

• Identify the tables and their relationships

• Determine the conditions to be used in the stored procedure

• Write the SQL code for the stored procedure

• Test the stored procedure to ensure it returns the desired results

To increase PHP memory at run time, modify the php.ini file or use ini_set() function.

• Edit the memory_limit value in php.ini file

• Use ini_set('memory_limit', '256M') function to increase memory limit at run time

• Check for memory leaks in the code

• Use unset() function to free up memory after use

php.ini is a configuration file for PHP that allows users to customize various settings.

• Change PHP settings such as memory limit, file upload size, and error reporting

• Enable or disable extensions and modules

• Set timezone and language settings

• Configure email settings

• Control caching and session settings

Use window.location to get domain from a url in jQuery.

• Use window.location to get the full url

• Use .hostname to get the domain name

• Use .replace() to remove 'www.' if present

WAP to find smallest palindrome number larger than given number.

• Convert the given number to string and check if it is already a palindrome.

• If not, increment the number and check if it is a palindrome.

• Repeat until a palindrome number larger than the given number is found.

• Use a while loop to implement the above steps.

WAP to check if linked list elements is a palindrome without using any extra space.

• Traverse the linked list and reverse the second half of the list

• Compare the first half with the reversed second half

• Use two pointers to traverse the list, one at normal speed and other at double speed

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.

Find the second largest prime number and its index from an array of positive integers.

• Iterate through the array and check if each number is prime

• Store the largest and second largest prime numbers found so far

• Also store their indices

• Return the second largest prime number and its index

Find the first missing positive number in an array of positive and negative integers.

• Sort the array in ascending order

• Iterate through the sorted array and find the first positive number that is missing

• If no positive number is missing, return the next positive number after the largest positive number in the array

The data structure to program a jigsaw puzzle program would be a graph.

• Use a graph data structure to represent the puzzle pieces and their connections.

• Each puzzle piece can be represented as a node in the graph.

• Edges between nodes represent the connections between puzzle pieces.

• To solve the puzzle, use graph traversal algorithms like depth-first search or breadth-first search.

• Apply puzzle-solving strategies like findin

Times Internet Limited (TIL) is a digital products company that operates various online platforms and services.

• TIL is a subsidiary of Bennett Coleman & Co. Ltd (BCCL), which is India's largest media conglomerate.

• TIL operates popular websites and apps like Times of India, Economic Times, Gaana, MX Player, and Cricbuzz.

• TIL focuses on digital content, e-commerce, and technology solutions.

• TIL has a diverse portfolio of...read more

I transitioned to software development due to my passion for coding and problem-solving.

• I discovered my interest in coding during my civil engineering studies

• I took online courses and attended coding bootcamps to learn software development skills

• I completed projects and internships in software development to gain practical experience

• I enjoy the creativity and problem-solving aspects of software development

The average speed can be calculated by taking the harmonic mean of the two speeds.

• To calculate the harmonic mean, divide the sum of the speeds by the reciprocal of the sum of their reciprocals.

• In this case, the harmonic mean can be calculated as 2/(1/20 + 1/30) = 24 km/h.

The minimum number of steps to find the defective ball is 2.

• Divide the 8 balls into 3 groups of 3, 3, and 2 balls.

• Compare the weights of the two groups of 3 balls.

• If one group is heavier, divide it into 2 balls and compare their weights.

• If the two balls have different weights, the heavier ball is the defective one.

• If the two balls have the same weight, the remaining ball in the first group of 3 is the defective one.

Polymorphism is the ability of an object to take on many forms. It allows objects of different classes to be treated as the same type.

• Polymorphism is achieved through method overriding and method overloading.

• Method overriding allows a subclass to provide a specific implementation of a method that is already defined in its superclass.

• Method overloading allows multiple methods with the same name but different parameters ...read more

Operator overloading is the ability to redefine operators for custom classes.

• Allows operators to be used with custom classes

• Example: '+' operator can be used to concatenate strings

• Can improve readability and simplify code

Method overloading is having multiple methods with the same name but different parameters. Method overriding is having a method in a subclass with the same name, return type, and parameters as a method in its superclass.

• Method overloading is achieved within the same class.

• Method overriding occurs in a subclass that inherits from a superclass.

• Method overloading is determined at compile-time based on the number, type, an...read more

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