This algorithm is also correct because it obtains the same answers as given in the project description and that it enumerates every single possible ordering of the tasks and compares them all. I know that it enumerates all orderings because the tree it creates and traverse is a complete tree, that is that length of the path from the root to all the leaves is the same. This algorithm does not solve the problem though because it does not give the schedule in its output. I can only hypothesize that it is correct because it does output the cost and that those numbers agree with the project description.