This is my problem:
In the below table:
1 -> 4
2 -> 5
4 -> 6
The above reads as follows...
Student 1 donates all of his/her money to Student 4
Student 2 donates all of his/her money to Student 5
Student 4 donates all of his/her money to Student 6
I would like to pull all of the ultimate donors from the above table. An ultimate donor is someone who is at all times a receptor and never a donor.
So in the above scenario Students 5 and 6 are ultimate donors. Does anyone have any ideas on how this can be accomplished?
I will be very appreciative of any inputs.