- The full-timers A, B, C, and D work 36 h/week, and hence can work
18 shifts of 8 hours in 4 weeks.

- The part-timers E, F, G, and H work 20 h/week, and hence can work
10 shifts of 8 hours in 4 weeks.

The day shift D starts at 8 AM and ends at 5 PM; there is a break from 12 to 1 PM.

The night shift N starts at 11 PM, and is shown in the schedule on the day it starts. The shifts ends at 7 AM the next day. The night shift starting at 11 PM on Friday is considered a weekend shift, as well the the shifts starting on Saturday and Sunday.

The scheduling period of 28 days is from January 2, 2006 to (inclusive) January 29, 2006.

The hard constraints are:

- To a full-timer 18 shifts have to be assigned.

- To a part-timer 10 shifts have to be assigned.
- Each day there starts at most one shift for an employee.

- Each employee gets at most 4 night shifts, of which at most 3 on
consecutive days.

- Each employee works at most 6 days in a row.

- Each any 3 consecutive weekend, at least one is free of labour.

- After a series of 1,2, or 3 night shifts, there is 48 hours free
of labour.

- A single night shift gets penalty 100. (A single night shift on January 29 is not penalised by this rule.)
- A stand-alone shift gets penalty 100 . (A stand-alone shift on January 29 is not penalised by this rule.)
- A weekend with 1 shift gets penalty 100.
- A rest of one day gets penalty 10. (Work on January 28, and rest on January 29 is not penalised by this rule.)
- A full-timer gets 4 or 5 shifts per week (from Monday till
Monday), and a part-timer 2 or 3. Penalty 1, 4, 9, 16 for deviation of
1, 2, 3 or 4.
- A full-timer gets series of length 4 to 6, and a part-timer of lengte 2 or 3. Penalty 1,4,9 for deviation 1,2,3. (Too short series at the end of the schedule are not penalised!)

To A: D on January 2 and D on January 3.

To C: D on January 2 and D on January 3.

To D: N on January 2 and N on January 3.

To E: D on January 2 and D on January 3.