All Tasks Scheduling Orders (hard)

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 print all possible ordering of tasks meeting all prerequisites.

Example 1:

Input: Tasks=3, Prerequisites=[0, 1], [1, 2]
Output: [0, 1, 2]
Explanation: There is only possible ordering of the tasks.

Example 2:

Input: Tasks=4, Prerequisites=[3, 2], [3, 0], [2, 0], [2, 1]
Output: 
1) [3, 2, 0, 1]
2) [3, 2, 1, 0]