Course Schedule II: Find Valid Course Order Topological Sort

amazon Given a directed graph representing course prerequisites with n courses and some prerequisite pairs, determine the order in which all courses should be taken. If it is not possible, return an empty list. Input: n: Total number of courses. prerequisites: An array where each element is [ai, bi] indicating course ai depends on course bi. Output: A list representing the course order or an empty list. Example: Input: n = 4, prerequisites = [[1,0],[2,0],[3,1],[3,2]] Output: [0,1,2,3] or [0,2,1,3] Input: n = 2, prerequisites = [[1,0],[0,1]] Output: [] Constraints: The total number of courses n is a positive integer. prerequisites is a 2D array of length m where ai and bi are integers between 0 and n-1. Example Input 4 [[1,0],[2,0],[3,1],[3,2]]