Copy Message on Long Press | Dataford Interview Questions

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Problem

SlackLite stores chat messages in order. Implement a function that processes a sequence of user actions and returns the copied text after each action while keeping message state consistent.

Each message has a unique integer id and a string text. An action is one of:

"long_press": if the message exists, copy its text and mark only that message as copied
"delete": remove the message; if it was the copied message, clear the copied state
"edit": update the message text; if it is currently copied, the clipboard should immediately reflect the new text

Return a list of clipboard values after every action. Use null when nothing is copied.

Formal Specification

Input: messages as a list of objects with keys id and text; actions as a list of objects with keys type, id, and optional text
Output: A list where each element is the current clipboard text after the corresponding action, or null

Constraints

1 <= len(messages) <= 10^5
1 <= len(actions) <= 10^5
1 <= id <= 10^9
0 <= len(text) <= 10^4
Message IDs in messages are unique

Function Signature

def process_copy_actions(messages, actions):