Question

He has some orders to deliver. you have a map of byteland, and there are n cities and m directed ways. you also have a set of k different cities where bill has to make a delivery. you have to find a good order of cities for bill to visit. the order c is good if and only if, it's possible to reach city number c[x+1] from city number c[x] for each acceptable x.

Answer 1

this is very long ok