Example 1:
Input: numCourses = 2, prerequisites = [[0,1]]
Output: true
Explanation:
Example 2:
Input: numCourses = 2, prerequisites = [[0,1],[1,0]]
Output: false
Explanation:
You are given an array prerequisites where prerequisites[i] = [a, b] indicates that you must take course b first if you want to take course a.
The pair [0, 1], indicates that must take course 1 before taking course 0.
There are a total of numCourses courses you are required to take, labeled from 0 to numCourses - 1.
Return true if it is possible to finish all courses, otherwise return false.
First take course 1 (no prerequisites) and then take course 0.
In order to take course 1 you must take course 0, and to take course 0 you must take course 1. So it is impossible.
1 <= numCourses <= 10000 <= prerequisites.length <= 1000prerequisites[i].length == 20 <= a[i], b[i] < numCoursesprerequisite pairs are unique.