Find All Dependencies

You are given a Task class that represents a unit of work and a list of its immediate prerequisites. There are two input lists: one containing every task in the system, and another holding the specific target tasks you care about.

Your job is to implement a method that returns every dependency required by those target tasks, presented in the order they must be completed, and without any duplicates.

Input

• all_tasks: a list of all Task objects.
• target_tasks: a list of the Task objects whose dependencies you need to collect.

Output

• A list of Task objects representing the complete set of dependencies, in valid execution order, with no repeating entries.

Example

Given the full set of tasks:

Task A: Dependencies []
Task B: Dependencies [A]
Task C: Dependencies [B]
Task D: Dependencies [A, C]

Target tasks: [D]

Output: [A, B, C]

Why this output: D directly needs A and C. C in turn needs B, and B needs A. Collecting them in dependency order (A before B before C) gives the required sequence without duplicates.

Constraints

• Number of tasks N ≤ 1000
• Number of dependency edges M ≤ 3000