Package g0201_0300.s0210_course_schedule_ii

Class Solution

java.lang.Object
g0201_0300.s0210_course_schedule_ii.Solution
public class Solution extends Object
210 - Course Schedule II\. Medium 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] = [ai, bi] indicates that you **must** take course bi first if you want to take course ai. * For example, the pair `[0, 1]`, indicates that to take course `0` you have to first take course `1`. Return _the ordering of courses you should take to finish all courses_. If there are many valid answers, return **any** of them. If it is impossible to finish all courses, return **an empty array**. **Example 1:** **Input:** numCourses = 2, prerequisites = \[\[1,0]] **Output:** [0,1] **Explanation:** There are a total of 2 courses to take. To take course 1 you should have finished course 0. So the correct course order is [0,1]. **Example 2:** **Input:** numCourses = 4, prerequisites = \[\[1,0],[2,0],[3,1],[3,2]] **Output:** [0,2,1,3] **Explanation:** There are a total of 4 courses to take. To take course 3 you should have finished both courses 1 and 2. Both courses 1 and 2 should be taken after you finished course 0. So one correct course order is [0,1,2,3]. Another correct ordering is [0,2,1,3]. **Example 3:** **Input:** numCourses = 1, prerequisites = [] **Output:** [0] **Constraints:** * `1 <= numCourses <= 2000` * `0 <= prerequisites.length <= numCourses * (numCourses - 1)` * `prerequisites[i].length == 2` * 0 <= ai, bi < numCourses * ai != bi * All the pairs [ai, bi] are **distinct**.

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • findOrder

      public int[] findOrder(int numCourses, int[][] prerequisites)