Department numbers: Difference between revisions

=={{header|Mercury}}==

<lang mercury>:- module department_numbers.

:- interface.

:- import_module io.

:- pred main(io::di, io::uo) is cc_multi.

:- implementation.

:- import_module int, list, solutions, string.

main(!IO) :-

io.print_line("P S F", !IO),

unsorted_aggregate(department_number, print_solution, !IO).

:- pred print_solution({int, int, int}::in, io::di, io::uo) is det.

print_solution({P, S, F}, !IO) :-

io.format("%d %d %d\n", [i(P), i(S), i(F)], !IO).

:- pred department_number({int, int, int}::out) is nondet.

department_number({Police, Sanitation, Fire}) :-

list.member(Police, [2, 4, 6]),

list.member(Sanitation, 1 .. 7),

list.member(Fire, 1 .. 7),

Police \= Sanitation,

Police \= Fire,

Sanitation \= Fire,

Police + Sanitation + Fire = 12.</lang>

{{out}}

<pre>P S F

2 3 7

2 4 6

2 6 4

2 7 3

4 1 7

4 2 6

4 3 5

4 5 3

4 6 2

4 7 1

6 1 5

6 2 4

6 4 2

6 5 1</pre>