Info Edge Sdet Interview Questions and Answers

Reverse every 3 nodes in a singly linked list using recursion.

• Create a recursive method that takes the head of the linked list as input.

• If the head is null or there are less than 3 nodes remaining, return the head.

• Reverse the first 3 nodes by swapping their pointers.

• Recursively call the method on the next 3 nodes and update the pointers accordingly.

• Return the new head of the reversed linked list.

1. Time management 2. Public speaking 3. Learning new technologies

• Struggling with time management, often missing deadlines

• Nervous when speaking in front of large groups

• Finding it challenging to keep up with the latest technologies in the field

Program to find the angle between the hands of a clock given the time.

• Calculate the angle of the hour hand from 12 o'clock position

• Calculate the angle of the minute hand from 12 o'clock position

• Calculate the absolute difference between the two angles

• If the difference is greater than 180 degrees, subtract it from 360 degrees

• Return the absolute value of the difference as the angle between the hands

To find if two linked lists intersect, traverse both lists and compare their tail nodes.

• Traverse both linked lists and find their lengths

• If the lengths are different, move the longer list's head pointer to the difference in length

• Now traverse both lists and compare their nodes until a common node is found

• If no common node is found, the lists do not intersect

JOINS are used to combine rows from two or more tables based on a related column between them.

• JOINS are used to retrieve data from multiple tables in a single query

• There are different types of JOINS - INNER, LEFT, RIGHT, FULL OUTER

• JOINS are based on a related column between the tables

• Syntax: SELECT * FROM table1 JOIN table2 ON table1.column = table2.column

Combine 4 elements of a sorted array of size 7 and a sorted array of 3 elements to make a sorted array.

• Insert the 3 elements of the smaller array into the larger array

• Sort the larger array using any sorting algorithm

To check if a string is a palindrome, compare the first and last characters, then move towards the center.

• Remove all non-alphanumeric characters and convert to lowercase

• Use two pointers, one starting from the beginning and the other from the end

• Compare the characters at both pointers, move towards the center until they meet

• If all characters match, the string is a palindrome

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