Task Manager OOD: Priority Queue with Deadlines and Cancellation

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## Problem Design and implement a `TaskManager` class that supports scheduling tasks with priorities and deadlines, executing the highest-priority due task, and cancelling pending tasks. ```python class TaskManager: def add_task(self, task_id: int, priority: int, deadline: int) -> None: """Add a task. deadline is an absolute timestamp.""" pass def cancel_task(self, task_id: int) -> bool: """Cancel a pending task. Return False if not found or already done.""" pass def execute_next(self, current_time: int) -> int | None: """Execute the highest-priority task whose deadline <= current_time. Return task_id, or None if no task is due.""" pass def get_pending(self) -> list[int]: """Return all pending task IDs in priority order.""" pass ``` ``` manager.add_task(1, priority=5, deadline=10) manager.add_task(2, priority=8, deadline=5) manager.add_task(3, priority=3, deadline=10) manager.execute_next(current_time=6) -> 2 (highest priority with deadline <= 6) manager.cancel_task(3) -> True manager.execute_next(current_time=10) -> 1 ``` ## Follow-ups 1. How do you handle lazy deletion from the heap after `cancel_task`? 2. What if two tasks share the same priority — what is your tiebreak? 3. How would you support recurring tasks that re-enqueue after execution? 4. How does your design change if `execute_next` must be thread-safe?

Task Manager OOD: Priority Queue with Deadlines and Cancellation

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