Three robots $($A$,$ B$,$ C$)$ have two hours to complete five tasks $(1,2,3,4,5).$ Each task takes one hour to complete, each robot can work on only one task at a time, and only one robot may work on a task at a time. Each robot is only equipped to perform certain tasks, as shown in the table.

Finally, task $1$ must be completed before task $2,$ and $3$ must be completed before $5.$ We can formulate this problem as a CSP$,$ using one variable for each task: $x1,$dots,$x5,$ whose possible values are a subset of $A1,A2,$dotsC$2,$ where $x5=C2$ means that task $5$ is done by robot $C$ and Time$($X$5)$ is $2.$ We have written the domain of each variable in the diagram below.

Robot Tasks

$\backslash$table$[[$A$,1,2,3$