Tasks Scheduling Order (medium)

Problem Statement

There are ‘N’ tasks, labeled from ‘0’ to ‘N-1’. Each task can have some prerequisite tasks which need to be completed before it can be scheduled. Given the number of tasks and a list of prerequisite pairs, write a method to find the ordering of tasks we should pick to finish all tasks.

Example 1:

Input: Tasks=3, Prerequisites=[0, 1], [1, 2]
Output: [0, 1, 2]
Explanation: To execute task '1', task '0' needs to finish first. Similarly, task '1' needs
to finish before '2' can be scheduled. A possible scheduling of tasks is: [0, 1, 2] 

Example 2:

Input: Tasks=3, Prerequisites=[0, 1], [1, 2], [2, 0]
Output: []
Explanation: The tasks have a cyclic dependency, therefore they cannot be scheduled.

Example 3:

Input:

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