A librarian assigns a numeric code to all the books

She maintains a key value pair to map the book name to the numeric code

Book shelves are marked with the numeric code

She follows a certain arrangement logic for storing her books

It is just that it is a digital library and the books are in the kindle format and the shelves are nothing but a certain space in her computer memory disk

When a customer requests a book, she searches for the book, retrieves the book from the digital shelf and issues the book to the customer

When a customer returns a book, she stores the book in the digital shelf

Design a data structure to search, store, retrieve books and use divide and conquer algorithm to implement that data structure.

Start the library with a fixed set of books. Get the book names from the input file and assign a code. Store the books in the digital library.