Call Me Services Interview Questions and Answers

Round duration - 90 minutes
Round difficulty - Medium

Questions on aptitude, English, logical reasoning, C/C++ and 5 coding ques. (only pseudo code).

Q1. 
Minimum Jumps Problem Statement
Bob and his wife are in the famous 'Arcade' mall in the city of Berland. This mall has a unique way of moving between shops using trampolines. Each shop is laid out in a st...read more
Ans. 
Find the minimum number of trampoline jumps Bob needs to make to reach the final shop, or return -1 if it's impossible.
• Use Breadth First Search (BFS) algorithm to find the minimum number of jumps required.

• Keep track of the visited shops to avoid revisiting them.

• If a shop has an Arr value of 0, it is impossible to reach the final shop.

• Return -1 if the final shop cannot be reached.
Answered by AI
Add your answer
Q2. 
Smallest Window Problem Statement
Given two strings, S and X, your task is to find the smallest substring in S that contains all the characters present in X.
Example:
Input:
S = "abdd", X = "bd"
Outpu...read more
Ans. 
Find the smallest substring in S that contains all characters in X.
• Use a sliding window approach to find the smallest window in S containing all characters of X.

• Maintain a hashmap to keep track of characters in X and their frequencies in the current window.

• Slide the window to the right, updating the hashmap and shrinking the window until all characters in X are present.

• Return the smallest window found.

• Example: S = 'abd
Answered by AI
Add your answer
Q3. 
Rat in a Maze Problem Statement
You need to determine all possible paths for a rat starting at position (0, 0) in a square maze to reach its destination at (N-1, N-1). The maze is represented as an N*N ma...read more
Ans. 
Find all possible paths for a rat in a maze from start to destination.
• Use backtracking to explore all possible paths in the maze.

• Keep track of visited cells to avoid revisiting them.

• Return paths in alphabetical order as a list of strings.
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Easy

Questions based on OOPS were asked in this round.

Q1. What is a virtual function?
Ans. 
A virtual function is a function in a base class that is declared using the keyword 'virtual' and can be overridden by a function with the same signature in a derived class.
• Virtual functions allow for dynamic polymorphism in C++

• They are used in inheritance to achieve runtime polymorphism

• Virtual functions are declared in a base class and can be overridden in derived classes

• They are called based on the type of object bei...read more
Answered by AI
Add your answer
Q2. What are the types of polymorphism in Object-Oriented Programming?
Ans. 
Types of polymorphism in OOP include compile-time (method overloading) and runtime (method overriding) polymorphism.
• Compile-time polymorphism is achieved through method overloading, where multiple methods have the same name but different parameters.

• Runtime polymorphism is achieved through method overriding, where a subclass provides a specific implementation of a method that is already defined in its superclass.

• Polymor...read more
Answered by AI
Add your answer
Q3. What is the difference between deep copy and shallow copy?
Ans. 
Deep copy creates a new object and recursively copies all nested objects, while shallow copy creates a new object and copies only the references to nested objects.
• Deep copy creates a new object and copies all nested objects, while shallow copy creates a new object and copies only the references to nested objects.

• In deep copy, changes made to the original object do not affect the copied object, while in shallow copy, ch...read more
Answered by AI
Add your answer

Round duration - 30 minutes
Round difficulty - Easy

HR round with typical behavioral problems.

Round duration - 60 minutes
Round difficulty - Easy

This was a written coding test with 2 coding questions to be solved in 60 minutes.

Q1. 
Find Missing Number In String Problem Statement
You have a sequence of consecutive nonnegative integers. By appending all integers end-to-end, you formed a string S without any separators. During this pro...read more
Ans. 
Given a string of consecutive nonnegative integers with one missing number, find the missing integer.
• Iterate through the string to find the missing number by checking the consecutive integers.

• If there is more than one missing number, all integers are present, or the string is invalid, return -1.

• Handle cases where the missing number is at the beginning or end of the sequence.

• Consider edge cases such as single-digit numb
Answered by AI
Add your answer
Q2. 
First Non-Repeating Character Problem Statement
You are given a string consisting of English alphabet characters. Your task is to identify and return the first character in the string that does not repeat...read more
Ans. 
The task is to find the first non-repeating character in a string, or return the first character if all characters repeat.
• Iterate through the string to count the frequency of each character

• Find the first character with a frequency of 1, or return the first character if no such character exists

• Handle both uppercase and lowercase characters separately

• Use a hashmap to store character frequencies efficiently
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Medium

Technical interview round with questions around PHP and DBMS.

Q1. What is connection pooling?
Ans. 
Connection pooling is a technique used to manage a pool of database connections to improve performance and efficiency.
• Connection pooling reduces the overhead of opening and closing database connections for each request.

• It allows multiple clients to reuse a pre-established set of connections to the database.

• Connection pooling helps in improving the scalability and performance of applications by efficiently managing data...read more
Answered by AI
Add your answer
Q2. How would you create a singleton design pattern in PHP 5?
Ans. 
To create a singleton design pattern in PHP 5, use a private static variable to store the instance and a static method to retrieve it.
• Create a private static variable to store the instance of the class.

• Create a private constructor to prevent outside instantiation of the class.

• Create a static method to check if an instance already exists and return it, or create a new instance if it doesn't.
Answered by AI
Add your answer
Q3. Can you write code to connect PHP to MySQL?
Ans. 
Yes, PHP can be used to connect to MySQL by using MySQLi or PDO extensions.
• Use MySQLi extension to connect PHP to MySQL

• Use PDO extension to connect PHP to MySQL

• Example using MySQLi: $conn = new mysqli($servername, $username, $password, $dbname);

• Example using PDO: $conn = new PDO('mysql:host=$servername;dbname=$dbname', $username, $password);
Answered by AI
Add your answer
Q4. What are the different types of errors in PHP?
Ans. 
Different types of errors in PHP include syntax errors, runtime errors, and logical errors.
• Syntax errors: Occur when there is a mistake in the code syntax, preventing the script from running.

• Runtime errors: Happen during script execution, such as division by zero or calling a function that does not exist.

• Logical errors: Difficult to detect as the code runs without errors, but produces incorrect results.

• Fatal errors: St...read more
Answered by AI
Add your answer
Q5. How does session management work in PHP?
Ans. 
Session management in PHP involves storing user data on the server to maintain state between multiple requests.
• Sessions are started using session_start() function in PHP.

• Session data is stored on the server and a unique session ID is sent to the client's browser.

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

• Sessions can be destroyed using session_destroy() function.
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Medium

Technical round where the interviewer asked me questions based on data structures , algorithms and load balancer and session management.

Q1. 
Pair Sum Problem Statement
You are given an integer array 'ARR' of size 'N' and an integer 'S'. Your task is to find and return a list of all pairs of elements where each sum of a pair equals 'S'.
Note:
...read more
Ans. 
Find pairs of elements in an array that sum up to a given value, sorted in a specific order.
• Iterate through the array and use a hashmap to store the difference between the target sum and each element.

• Check if the difference exists in the hashmap, if so, add the pair to the result list.

• Sort the result list based on the criteria mentioned in the problem statement.
Answered by AI
Add your answer
Q2. 
Next Smallest Palindrome Problem Statement
Find the next smallest palindrome strictly greater than a given number 'N' represented as a string 'S'.
Explanation:
You are given a number in string format, a...read more
Ans. 
Find the next smallest palindrome greater than a given number represented as a string.
• Convert the string number to an integer for comparison.

• Increment the number until a palindrome greater than the input is found.

• Handle cases where the input is already a palindrome or has leading zeros.

• Return the next greater palindrome as a string.
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Medium

Technical round where the interviewer asked me questions based on data structures , design patterns and php.

Q1. 
Check If Linked List Is Palindrome
Given a singly linked list of integers, determine if the linked list is a palindrome.
Explanation:
A linked list is considered a palindrome if it reads the same forwar...read more
Ans. 
Check if a given singly linked list of integers is a palindrome.
• Create a function to reverse the linked list.

• Use slow and fast pointers to find the middle of the linked list.

• Compare the first half of the linked list with the reversed second half to determine if it's a palindrome.
Answered by AI
Add your answer
Q2. Can you explain the implementation of the Singleton Design pattern?
Ans. 
Singleton Design pattern ensures a class has only one instance and provides a global point of access to it.
• Ensure the class has a private static instance variable.

• Provide a public static method to access the instance.

• Make the constructor private to prevent instantiation from outside the class.

• Lazy initialization can be used to create the instance only when needed.

• Thread safety considerations may be necessary in a multi
Answered by AI
Add your answer

Round duration - 60 minutes
Round difficulty - Medium

Technical round where the interviewer asked me questions based on Javascript, dbms, oops concepts and php.

Q1. Write a stored procedure to join two tables.
Ans. 
A stored procedure to join two tables in a database.
• Use the JOIN keyword to combine rows from two or more tables based on a related column between them.

• Specify the columns to be selected from each table in the SELECT statement.

• Use the ON keyword to specify the join condition.

• Consider using INNER JOIN, LEFT JOIN, RIGHT JOIN, or FULL JOIN based on the desired result.

• Test the stored procedure with sample data to ensure it
Answered by AI
Add your answer
Q2. What is the difference between an abstract class and an interface in Object-Oriented Programming?
Ans. 
Abstract class can have both abstract and non-abstract methods, while interface can only have abstract methods.
• Abstract class can have constructors, fields, and methods, while interface cannot have any implementation.

• A class can only extend one abstract class, but can implement multiple interfaces.

• Abstract classes are used to define common characteristics among subclasses, while interfaces are used to define a contract...read more
Answered by AI
Add your answer
Q3. How can you extract the domain name from a URL using jQuery?
Ans. 
Use jQuery to extract domain name from a URL
• Use the 'a' element to create a temporary link with the URL

• Access the 'hostname' property of the link to get the domain name

• Use regular expressions to extract the domain name from the URL
Answered by AI
Add your answer
Q4. What are closures in JavaScript?
Ans. 
Closures in JavaScript are functions that have access to variables from their outer scope even after the outer function has finished executing.
• Closures allow functions to access variables from their parent function even after the parent function has finished executing.

• They are created whenever a function is defined within another function.

• Closures are commonly used to create private variables and functions in JavaScrip...read more
Answered by AI
Add your answer