Parallel Courses II

Given n courses with prerequisites and a limit k on courses per semester, find the minimum number of semesters needed to complete all courses.

Examples
Input: [4,[[2,1],[3,1],[1,4]],2]
Output: 3
Hints

Parallel Courses II

Given n courses with prerequisites and a limit k on courses per semester, find the minimum number of semesters needed to complete all courses.