There are 4 hosts numbered from 0 to 3, and 2 tasks numbered from 0 to 1. Each host has a set of tasks that it is interested in: 
Host 0 is interested in task 1.
Host 2 is interested in task 0.
Host 0 is interested in task 0.
Host 2 is interested in task 1.
Host 3 is interested in task 1.
Host 3 is interested in task 0.
Host 1 is interested in task 0..