Library Management System

You are required to build a simple library management system. The system should allow adding books and querying them either by author or by publication year.

Each book has a title, an author, and a publication year. When queried, the results should be returned in lexicographical order (i.e., sorted based on ASCII values).

The system supports three types of queries:

• ADD: Add a new book. The command format is: ADD title author year.
• AUTHOR: Retrieve all books written by a specific author. The command format is: AUTHOR author.
• YEAR: Retrieve all books published in a specific year. The command format is: YEAR year.

For queries of type AUTHOR and YEAR, output the matching book titles in lexicographical order, separated by commas. If no books match the query, output an empty line.

Note: Titles and authors will not contain spaces. Use underscores (_) to represent spaces if needed.

inputFormat

The first line of input contains an integer Q, which represents the number of queries. The following Q lines each contain a query. Each query can be one of the following:

1. ADD title author year

   • title: a string (without spaces, use underscores instead)
   • author: a string (without spaces, use underscores instead)
   • year: an integer representing the publication year.

2. AUTHOR author

   • Retrieves all book titles by the given author.

3. YEAR year

   • Retrieves all book titles published in the given year.

All tokens are separated by a single space.

outputFormat

For each query of type AUTHOR or YEAR, output a single line containing the sorted book titles separated by commas. If no books match the query, output an empty line.## sample

6
ADD The_Great_Gatsby F._Scott_Fitzgerald 1925
ADD 1984 George_Orwell 1949
ADD Animal_Farm George_Orwell 1945
AUTHOR George_Orwell
YEAR 1925
AUTHOR Unknown

1984,Animal_Farm
The_Great_Gatsby