Solution to frietkot problem

frietkot.py

# solution to the Frietkot problem https://people.cs.kuleuven.be/~tias.guns/frietkot/ using pysat

from pysat.solvers import Solver
MAYONNAISE = 1
KETCHUP = 2
CURRY = 3
ANDALOUSE = 4
SAMURAI = 5


nora = [MAYONNAISE, KETCHUP ]
leander = [ -SAMURAI , MAYONNAISE ]
benjamin = [ -ANDALOUSE , -CURRY , -SAMURAI]
behrouz = [KETCHUP , CURRY , ANDALOUSE ]
guy = [ -KETCHUP , CURRY , ANDALOUSE ]
daan = [ -KETCHUP , -CURRY , ANDALOUSE ]
celine = [ -SAMURAI ]
anton = [ MAYONNAISE , -CURRY , -ANDALOUSE ]
danny = [ -MAYONNAISE , KETCHUP , ANDALOUSE , SAMURAI ]
luc = [ -MAYONNAISE , SAMURAI]


friends = [
    nora,
    leander,
    benjamin,
    behrouz,
    guy,
    daan,
    celine,
    anton,
    danny,
    luc
]

solver = Solver(name='m22')

for friend in friends:
    solver.add_clause(clause=friend)

solver.solve()

print(solver.get_model())

# prints -1, 2, -3, 4, -5 -- which is
# !mayonnaise, ketchup, !curry_ketchup, andalouse, !samurai