topological sort

topological_sort(N, adj[N][N])
        T = []
        visited = []
        in_degree = []
        for i = 0 to N
                in_degree[i] = visited[i] = 0

        for i = 0 to N
                for j = 0 to N
                        if adj[i][j] is TRUE
                                in_degree[j] = in_degree[j] + 1

        for i = 0 to N
                if in_degree[i] is 0
                        enqueue(Queue, i)
                        visited[i] = TRUE

        while Queue is not Empty
                vertex = get_front(Queue)
                dequeue(Queue)
                T.append(vertex)
                for j = 0 to N
                        if adj[vertex][j] is TRUE and visited[j] is FALSE
                                in_degree[j] = in_degree[j] - 1
                                if in_degree[j] is 0
                                        enqueue(Queue, j)
                                        visited[j] = TRUE
        return T