Course Schedule II
Examples
Example 1:
Input: numCourses = 2, prerequisites = [[1,0]]
Output: [0,1]
Example 2:
Input: numCourses = 2, prerequisites = [[1,0],[0,1]]
Output: []
Explanation:
Example 1:
Input: numCourses = 2, prerequisites = [[1,0]]
Output: [0,1]
Example 2:
Input: numCourses = 2, prerequisites = [[1,0],[0,1]]
Output: []
Explanation:
There are a total of numCourses courses you have to take, labeled from 0 to numCourses - 1.
You are given an array prerequisites where prerequisites[i] = [a, b] indicates you must take course b before course a.
Return a valid order to finish all courses. If it is impossible to finish all courses, return an empty array.
The prerequisite graph has a cycle.
1 <= numCourses <= 20000 <= prerequisites.length <= 5000prerequisites[i].length == 20 <= a, b < numCoursesa != b