class Solution:
    def findOrder(self, numCourses: int, prerequisites: List[List[int]]) -> List[int]:

        Dict = collections.defaultdict(list)
        Indegree = collections.defaultdict(int)

        for ele in prerequisites:
            Dict[ele[1]].append(ele[0])
            Indegree[ele[0]] += 1

        res = []

        Q = collections.deque([])

        for i in range(numCourses):
            if Indegree[i] == 0:
                Q.append(i)
                del Indegree[i]

        if not Q:
            return res

        while Q:
            parent = Q.popleft()
            res.append(parent)

            for child in Dict[parent]:
                Indegree[child] -= 1
                if Indegree[child] == 0:
                    Q.append(child)

                    del Indegree[child]
        if len(Indegree) > 0:
            return []
        else:
            return res