Class Solution


  • public class Solution
    extends Object
    207 - Course Schedule.

    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 true if you can finish all courses. Otherwise, return false.

    Example 1:

    Input: numCourses = 2, prerequisites = [[1,0]]

    Output: true

    Explanation: There are a total of 2 courses to take. To take course 1 you should have finished course 0. So it is possible.

    Example 2:

    Input: numCourses = 2, prerequisites = [[1,0],[0,1]]

    Output: false

    Explanation: There are a total of 2 courses to take. To take course 1 you should have finished course 0, and to take course 0 you should also have finished course 1. So it is impossible.

    Constraints:

    • 1 <= numCourses <= 105
    • 0 <= prerequisites.length <= 5000
    • prerequisites[i].length == 2
    • 0 <= ai, bi < numCourses
    • All the pairs prerequisites[i] are unique.
    • Constructor Detail

      • Solution

        public Solution()
    • Method Detail

      • canFinish

        public boolean canFinish​(int numCourses,
                                 int[][] prerequisites)