Course schedule II

class Graph:
    def __init__(self,x,mylist):
        self.label=x
        self.neighbors=mylist

class Solution:
    """
    @param: numCourses: a total of n courses
    @param: prerequisites: a list of prerequisite pairs
    @return: the course order
    """
    def findOrder(self, numCourses, prerequisites):
        # write your code here
        if len(prerequisites)==0:
            return [i for i in range(numCourses)]


        all_course=[[i] for i in range(numCourses)]
        for i in range(len(prerequisites)):
            all_course[prerequisites[i][0]].append(prerequisites[i][1])

        start_point=False
        graphs=[]
        for i in range(len(all_course)):
            #temp_graph=Graph(i)
            if len(all_course[i])>1:
                graphs.append(Graph(i,all_course[i][1:]))
            else:
                start_point=True
                graphs.append(Graph(i,[]))

        #print(graphs[0].label)

        if not start_point:
            return []

        course_taken={}
        course_order=[]
        def topsort(mygraph):
            if mygraph.label in course_taken:
                return

            if len(mygraph.neighbors)>0:
                for i in range(len(mygraph.neighbors)):
                    topsort(mygraph.neighbors[i])
            course_taken[mygraph.label]=1
            course_order.append(mygraph.label)

        for i in range(len(graphs)):
            #print(graphs[i][0])
            topsort(graphs[i])
            if len(course_taken)==numCourses:
                break

        return course_order[::-1]