Track Remaining Cards Counter

EasyPython

Problem

An Ironclad Workflow Designer review queue contains uniquely identified cards. Implement a counter that reports how many cards remain as cards are drawn, returned, or queried.

Write a function that processes an initial collection of card IDs and an ordered list of operations. A draw operation removes a card, a return operation adds a previously drawn card back, and a display operation records the current number of remaining cards.

Formal Specification

Implement remaining_card_counts(card_ids, operations).

card_ids is a list of unique strings representing the cards initially in the queue.
operations is a list of two-element lists. Each operation is either ["draw", card_id], ["return", card_id], or ["display", null].
Return a list of integers containing the remaining-card count for every display operation, in order.
Every draw targets a currently remaining card, and every return targets a card that is currently absent.

Constraints

0 <= len(card_ids) <= 10^5
0 <= len(operations) <= 2 * 10^5
Card IDs are non-empty strings
Card IDs are unique in card_ids
Every draw targets a remaining card
Every return targets a card that is not remaining

Function Signature

def remaining_card_counts(card_ids, operations):

An Ironclad Workflow Designer review queue contains uniquely identified cards. Implement a counter that reports how many cards remain as cards are drawn, returned, or queried.

Formal Specification

Implement remaining_card_counts(card_ids, operations).

card_ids is a list of unique strings representing the cards initially in the queue.
operations is a list of two-element lists. Each operation is either ["draw", card_id], ["return", card_id], or ["display", null].
Return a list of integers containing the remaining-card count for every display operation, in order.
Every draw targets a currently remaining card, and every return targets a card that is currently absent.