Task Dependency Scheduler

Given a total number of tasks represented by unique integers from 0 to n-1 and a list of dependency pairs, write a function that returns a valid order in which the tasks can be completed. Each dependency pair [a, b] indicates that task 'a' must be finished before task 'b' can start. If it is impossible to finish all tasks due to a cycle in the dependency graph, the function should return an empty list.

Input

• An integer n representing the total number of tasks.
• A list of pairs (arrays/lists) where each pair [a, b] represents a dependency (task a must be completed before task b).

Output

• A list (or array) of task identifiers that represents a valid order in which the tasks can be completed. If multiple valid orders exist, returning any one of them is acceptable. If no valid order exists due to a cycle, return an empty list.

Example

Input:

n = 4
dependencies = [[1, 0], [2, 0], [3, 1], [3, 2]]

Possible Output:

[1, 2, 0, 3]

The output [2, 1, 0, 3] is also valid.

Requirements

• The solution should efficiently handle cases where the number of tasks and dependency pairs can be large.
• You may implement your solution in the programming language of your choice.
• Consider edge cases such as an empty dependency list or a scenario where tasks are completely independent.