## Problem Implement a `TODOList` class that manages tasks with priorities and optional deadlines. The list should always return the highest-priority, earliest-deadline task next. ```python import heapq from dataclasses import dataclass, field from datetime import datetime from typing import Optional @dataclass(order=True) class Task: priority: int # lower = higher priority deadline: Optional[datetime] id: int = field(compare=False) title: str = field(compare=False) class TODOList: def add(self, title: str, priority: int, deadline: Optional[datetime] = None) -> int: ... def next(self) -> Optional[Task]: ... def complete(self, task_id: int) -> bool: ... def pending(self) -> list[Task]: ... ``` **Example:** ``` add("File taxes", priority=1, deadline=2024-04-15) add("Buy milk", priority=2) next() -> Task("File taxes", priority=1, ...) ``` ## Follow-ups 1. How do you handle lazy deletion for `complete()` efficiently with a heap? 2. What happens if two tasks have equal priority and no deadline? 3. How would you add recurring tasks that re-insert after completion? 4. How would you persist and restore the list across process restarts?

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TODO List: Implement a TODO List Class with Priority Queue and Deadline Sorting

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Problem Implement a TODOList class that manages tasks with priorities and optional deadlines. The list should always return the highest-priority, earliest-deadline task next. Example: Follow-ups How do you handle lazy deletion for complete() efficiently with a heap? What happens if two tasks have equal priority and no deadline? How would you add recurring tasks that re-insert after completion? How would you persist and restore the list across process restarts?

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This is a reported interview question from a notion interview during the onsite round.

It covers the following topics: Coding, Queue, Heap, Onsite .

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TODO List: Implement a TODO List Class with Priority Queue and Deadline Sorting

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