Course Schedule
Question
You're given a total number of courses to take and a 2D list that represents the prerequisites required for each course.
For example, [(4, 1), (2, 3)] means that you need to take course 4 BEFORE you can take course 1, and that you need to take course 2 BEFORE you can take course 3.
Return the ordered class schedule you can follow to finish all courses. If it's impossible to finish all courses, return an empty list.
Input: total = 2, prereqs = [(0, 1)]
Output: [0, 1]
You must take course 0 first before taking course 1. The solution is take course 0, then course 1.
Input: total = 2, prereqs = [(0, 1), (1, 0)]
Output: []
In this case, the 2 courses are prerequisites of each other, thus the scenario is impossible.
Input: total = 5, prereqs = [(0, 2), (1, 2), (2, 4), (3, 4)]
Output: [0, 1, 3, 2, 4]
The output follows the prerequisite ordering provided.
Note that other variations would be accepted as answers too:
- [1, 0, 3, 2, 4]
- [1, 3, 0, 2, 4]
- [0, 3, 1, 2, 4]
Clarify the problem
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Understand the problem
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