Airtel Africa Software Engineer Interview Questions and Answers

Finding index of an element in a sorted, n-bit rotated array.

• Use binary search to find the pivot point where the array is rotated.

• Determine which side of the pivot point the target element lies.

• Perform binary search on the appropriate side of the pivot to find the target element.

• Handle edge cases such as when the target element is the pivot point itself.

Merge two sorted linked lists without using extra space

• Traverse both lists simultaneously and compare nodes

• Attach smaller node to result list and move pointer to next node

• Repeat until both lists are exhausted

• Return the head of the merged list

Find the first character with least occurrence in a string

• Iterate through the string and count the occurrence of each character

• Find the character with the least occurrence

• Return the first occurrence of that character

Difference between @Controller and @RestController

• Both are used for handling HTTP requests in Spring framework

• @Controller returns a view while @RestController returns data in JSON/XML format

• @RestController is a combination of @Controller and @ResponseBody annotations

• Use @Controller for traditional web applications and @RestController for RESTful web services

Both @Bean and @Component are used for creating beans in Spring framework.

• The @Bean annotation is used to explicitly declare a single bean.

• The @Component annotation is used to declare a class as a Spring component.

• The @Bean method is used in a configuration class to create and configure a bean.

• The @Component annotation is used on a class to indicate that it is a Spring-managed component.

• The @Bean method can be used to ...read more

Annotations used in Spring Framework for different layers of application

• All are used for dependency injection and component scanning

• @Service is used for service layer

• @Repository is used for data access layer

• @Component is used for general purpose beans

• @Controller is used for MVC controller layer

Dependency injection is a design pattern that allows objects to receive dependencies from external sources, while inversion of control is a principle that states that the control of object creation and lifecycle should be handed over to a container or framework.

• Dependency injection is a way to achieve loose coupling between objects

• Inversion of control is a principle that promotes decoupling of components

• Dependency inje...read more