Design a waitlist manager

Design a Waitlist Manager

Design a WaitlistManager class that maintains a list of parties waiting for a table at a restaurant. Each party is represented by a unique party_id (integer) and the number of people in the party.

You need to implement the following methods:

• add_party(party_id, num_people): Adds a new party to the end of the waitlist. If the party_id already exists, return False. Otherwise, add them and return True.
• seat_party(party_id): Removes the party from the waitlist because they have been seated. If the party_id is not in the waitlist, return False. Otherwise, return True.
• get_position(party_id): Returns the current position (1-indexed) of the party in the queue. If the party_id is not in the waitlist, return -1.
• get_next_party(): Returns the party_id of the party at the front of the queue, or -1 if the waitlist is empty.

Constraints

• party_id is a unique positive integer.
• The number of operations can be up to 10^5.
• get_position should be faster than O(n).

Example

manager = WaitlistManager()
manager.add_party(101, 4) # Returns True
manager.add_party(102, 2) # Returns True
manager.get_position(102) # Returns 2
manager.seat_party(101)   # Returns True
manager.get_position(102) # Returns 1