Moderator List Hierarchy

Problem Overview

Implement a Reddit-style moderator list from a newline-delimited log string. The interview usually comes in three parts:

• A single mod list
• Multiple communities
• Demotions that reorder the current mod list The core rule is: [Source: darkinterview.com]
• A moderator can remove another moderator only if they are above that moderator in the current mod list.
• Higher in the list means the moderator has an earlier effective access timestamp. In the first part, each log line has four comma-separated fields: `target, action, actor, timestamp
• target: the moderator receiving the action
• action: add or remove in Parts 1 and 2, plus demote in Part 3
• actor: the moderator who performed the action
• timestamp: integer timestamp, increasing over time Assume:
• The logs are already sorted by timestamp
• In Part 1, timestamps are unique
• In Parts 2 and 3, timestamps are unique within each community
• Every logged action is valid
• SYSTEM may appear as an actor to seed the first moderator, but SYSTEM is not part of the returned mod list unless explicitly added
• If a removed moderator is added again later, they get a new access timestamp Each part asks for the same three operations: [Source: darkinterview.com]
• Constructor: build the state from the log string
• can_remove_mod(...)
• get_mod_list(...)

Part 1: Single Moderator List

Problem Statement

Implement a class for a single moderator list: `class ModList: def init(self, logs: str): $L45 $L46($L47) -> $L48: $L4a $L4b($L4c) -> $L4d[$L4e]: