In a directed graph i want to call bfs on some of the vertices so that all of the vertices will be met.
(in other words all of the other vertices are reachable from these chosen vertices.)
I want to find the minimum number of such vertices.
Actually this problem arises in social networks when we want to find the minimum number of people to which if we send a message then all of the network members will get that.(suppose that we know when someone gets the message he/she will send that to all of his/her followers.)
Can anyone help?