Airtel Africa Interview Questions and Answers

A linked list is a data structure where each element points to the next element in the sequence.

• Create a Node class with data and next pointer

• Initialize a head pointer to the first node

• Traverse the list by following the next pointers

• Insert and delete nodes by updating pointers accordingly

Other methods of linked list include doubly linked list, circular linked list, and sorted linked list.

• Doubly linked list: Each node has a reference to the next and previous node.

• Circular linked list: Last node points back to the first node, forming a circle.

• Sorted linked list: Nodes are arranged in a sorted order based on a specific criteria.

The start point of a linked list is the first node in the list.

• The start point is typically referred to as the 'head' of the linked list.

• It is the entry point for traversing the linked list.

• Example: In a linked list with nodes A -> B -> C, A would be the start point.

A qualifier in Java is a keyword used to specify additional information about a variable or method.

• Qualifiers include 'final', 'static', 'abstract', 'public', 'private', 'protected', etc.

• They are used to define the behavior and access level of variables and methods.

• For example, 'final' qualifier makes a variable constant and 'static' qualifier allows a method to be called without creating an instance of the class.

Primary annotation is used to indicate the primary key in a database table.

• Primary annotation is used in Java Persistence API (JPA) to specify the primary key of an entity.

• It is used with @Id annotation to define the primary key field in a database table.

• Example: @Entity @Table(name = "employees") public class Employee { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "employee_id") p

Design a system similar to cars24, discussing components and design patterns.

• Components: User interface, database, search engine, recommendation engine, payment gateway

• Design pattern: Model-View-Controller (MVC)

• User interface: Allow users to search for cars, view car details, and make purchases

• Database: Store car information, user details, and transaction history

• Search engine: Enable users to search for cars based on v...read more

Code to find the maximum time occupied room given meeting slots.

• Sort the meeting slots based on start time.

• Iterate through the sorted slots and keep track of the maximum occupied time.

• Check for overlapping slots and update the maximum occupied time accordingly.

Code for singleton design pattern, binary search, and finding minimum number of coins needed

• For singleton design pattern, create a private static instance variable and a private constructor

• For binary search, divide the array in half and compare the middle element with the target

• For finding minimum number of coins, use dynamic programming and iterate through the denominations

Find pairs in a list of integers that sum to a specified target value.

• Use a hash map to store numbers and their indices for quick lookup.

• Iterate through the list and check if (target - current number) exists in the hash map.

• Example: For list [1, 2, 3, 4] and target 5, pairs are (1, 4) and (2, 3).

• Consider edge cases like duplicates and negative numbers.