Given numCourses courses (labeled 0 to numCourses-1) and prerequisites where prerequisites[i] = [a, b] means:
b before taking course aDetermine if it's possible to finish all courses.
Constraints:
Examples:
// Example 1:
const numCourses1 = 2;
const prerequisites1 = [[0, 1]];
console.log(canFinish(numCourses1, prerequisites1));
// Output: true
// Explanation: Take course 1 first, then course 0
// Example 2:
const numCourses2 = 2;
const prerequisites2 = [
[0, 1],
[1, 0],
];
console.log(canFinish(numCourses2, prerequisites2));
// Output: false
// Explanation: Courses 0 and 1 form a cycle, impossible