อ.สั่งงานให้ผม แล้วให้แก้ปัญหา Zebra Puzzle ที่ว่า มีคน 5 คน แต่ละคน ทำงานต่างกัน ดื่มเครื่องดื่มต่างกัน มีสัตว์เลี้ยงต่างกัน มีสัญชาติต่างกัน แล้วมีบ้านสีต่างกัน แล้วให้หาว่า ใครเลี้ยงม้าลาย แล้วใครดื่มน้ำเปล่า จากเงื่อนไขต่อไปนี้

colors        = "red white green yellow blue"
nationalities = "English Spanish Japanese Italian Norwegian"
pets          = "dog snails fox horse zebra"
drinks        = "tea, orange juice, milk, coffe, water"
jobs          = "painter diplomat photographer violinist physician"

#The English man lives in the red house.
#The Spanish owns a dog.
#The Japanese man is a painter.
#The Italians drinks tea.
#The Norwegian lives in the first house on the left.
#The green house is immediately to the right of the white one.
#The photographer breeds snails.
#The diplomat lives in the yellow house.
#Milk is drunk in the middle house.
#The owner of the green house drinks coffe.
#The Norwegians's house is next ot the blue one.
#The violinist drinks orange juice.
#The fox is in the house next to that of the physician.
#The horse is in a house next to that diplomat.

ผมได้ลองค้นหาหลายวิธีมาก แต่ส่วนใหญ่เป็น ai ทำให้ผมต้อง import module มาใช้ แต่ อ.ไม่ให้ import และไม่ได้สอนเรื่อง ai เลย แม้แต่น้อย ผมกำลังเรียนวิชา Discrete Mathematics ครับ ท่านใดทราบวิธีแก้ปัญหานี้ ช่วยแสดงความคิดเห็นหน่อยครับ

from constraint import AllDifferentConstraint, InSetConstraint, Problem

# variables
colors        = "red white green yellow blue".split()
nationalities = "English Spanish Japanese Italian Norwegian".split()
pets          = "dog snails fox horse zebra".split()
drinks        = "tea, orange juice, milk, coffe, water".split(", ")
jobs          = "painter diplomat photographer violinist physician".split(" ")

minn, maxn = 1, 5
problem = Problem()
variables = colors + nationalities + pets + drinks + jobs
problem.addVariables(variables, [1, 2, 3, 4, 5])


# Five men with different nationalities and with different jobs lives in consecutive houses on a street.
# These houses are painted different colors.
# The men have have different pets and drink different drinks.

for vars_ in (colors, nationalities, pets, drinks, jobs):
    problem.addConstraint(AllDifferentConstraint(), vars_)
    
#The English man lives in the red house.
#The Spanish owns a dog.
#The Japanese man is a painter.
#The Italians drinks tea.
#The Norwegian lives in the first house on the left.
#The green house is immediately to the right of the white one.
#The photographer breeds snails.
#The diplomat lives in the yellow house.
#Milk is drunk in the middle house.
#The owner of the green house drinks coffe.
#The Norwegians's house is next ot the blue one.
#The violinist drinks orange juice.
#The fox is in the house next to that of the physician.
#The horse is in a house next to that diplomat.

#Milk is drunk in the middle house.
problem.addConstraint(InSetConstraint([3]), ["milk"])
#The Norwegian lives in the first house on the left.
problem.addConstraint(InSetConstraint([1]), ["Norwegian"])
# The green house is on the right side of the white house.
problem.addConstraint(lambda a,b: a+1 == b, ["white", "green"])

def add_constraints(constraint, statements, variables=variables, problem=problem):
    for stmt in (line for line in statements if line.strip()):
        problem.addConstraint(constraint, [v for v in variables if v in stmt])

_statements = """
The owner of the green house drinks coffe.
The photographer breeds snails.
The English man lives in the red house.     
The Italian drinks tea.
The diplomat lives in the yellow house.
The violinist drinks orange juice.
The Japanese man is a painter.
The Spanish owns a dog.
""".split("\n")
add_constraints(lambda a,b: a == b, _statements)

nextto_statements = """
The Norwegian house is next to the right the blue one.
The fox is in the house next to that of the physician.
The horse is in a house next to that diplomat.
""".split("\n")
add_constraints(lambda a,b: abs(a - b) == 1, nextto_statements) #abs = absolute



def solve(variables=variables, problem=problem):
    from itertools  import groupby
    from operator   import itemgetter

    # find & print solutions
    for solution in problem.getSolutionIter():
        for key, group in groupby(sorted(solution.iteritems(), key=itemgetter(1)), key=itemgetter(1)):
            print (key)
            for v in sorted(dict(group).keys(), key=variables.index):
                print (v.ljust(9))
            print

if __name__ == '__main__':
    solve()