Course Schedule

Statement

You are given an integer, num_courses, representing the total number of courses you need to complete, labeled from 0 to num_courses - 1.

You are also given a prerequisites array, where prerequisites[i] = [a[i], b[i]] indicates that you must take course b[i] first if you want to take the course a[i]. For example, the pair $[1, 0]$ indicates that to take course $1$ ...