869. Course Schedule II
Medium•
This problem builds on course-schedule. Complete that first, then load your solution to continue.
There are numCourses courses labeled 0 through numCourses - 1. Each pair [course, prerequisite] means the prerequisite must be completed before that course.
Return an ordering containing every course exactly once that satisfies all dependencies. If several orderings work, return any of them. Return [] if a cycle makes completion impossible. Include courses without prerequisites and isolated courses. Unlike Course Schedule, this variant must construct a valid order rather than return a boolean.
Example 1:
Input: findOrder(2, [[1, 0]])
Output: [0, 1]
Explanation: Course 0 must appear before course 1.
Example 2:
Input: findOrder(4, [[1, 0], [2, 0], [3, 1], [3, 2]])
Output: [0, 1, 2, 3]
Explanation: Both 1 and 2 need 0; course 3 needs both. Either middle order works.
Example 3:
Input: findOrder(1, [])
Output: [0]
Explanation: The only course has no prerequisites.
Constraints
- 1 <= numCourses <= 2000
- 0 <= prerequisites.length <= numCourses * (numCourses - 1)
- Each pair contains two distinct course labels in range.
- All prerequisite pairs are distinct.
Accepted2/3|Acceptance Rate66.7%