| 1 | | def drinks_water(): |
| 2 | | pass |
| 1 | import itertools |
| 3 | 2 | |
| 3 | def drinks_water(): |
| 4 | """Returns the nationality of the person who drinks water.""" |
| 5 | solution = solve_puzzle() |
| 6 | for house in solution: |
| 7 | if house['drink'] == 'water': |
| 8 | return house['nationality'] |
| 9 | return None |
| 4 | 10 | |
| 5 | 11 | def owns_zebra(): |
| 6 | | pass |
| 12 | """Returns the nationality of the person who owns the zebra.""" |
| 13 | solution = solve_puzzle() |
| 14 | for house in solution: |
| 15 | if house['pet'] == 'zebra': |
| 16 | return house['nationality'] |
| 17 | return None |
| 18 | |
| 19 | def solve_puzzle(): |
| 20 | """ |
| 21 | Solves the Zebra Puzzle using constraint satisfaction. |
| 22 | Returns a list of 5 dictionaries, each representing a house with its attributes. |
| 23 | """ |
| 24 | # Define the possible values for each category |
| 25 | nationalities = ['Englishman', 'Spaniard', 'Ukrainian', 'Norwegian', 'Japanese'] |
| 26 | colors = ['red', 'green', 'ivory', 'yellow', 'blue'] |
| 27 | pets = ['dog', 'snail', 'fox', 'horse', 'zebra'] |
| 28 | drinks = ['coffee', 'tea', 'milk', 'orange juice', 'water'] |
| 29 | hobbies = ['dancing', 'painting', 'reading', 'football', 'chess'] |
| 30 | |
| 31 | # Generate all possible permutations for each category |
| 32 | for nationality_perm in itertools.permutations(nationalities): |
| 33 | # Constraint 10: The Norwegian lives in the first house |
| 34 | if nationality_perm[0] != 'Norwegian': |
| 35 | continue |
| 36 | |
| 37 | for color_perm in itertools.permutations(colors): |
| 38 | # Constraint 15: The Norwegian lives next to the blue house |
| 39 | if color_perm[1] != 'blue': |
| 40 | continue |
| 41 | |
| 42 | # Constraint 6: The green house is immediately to the right of the ivory house |
| 43 | found_ivory_green = False |
| 44 | for i in range(4): |
| 45 | if color_perm[i] == 'ivory' and color_perm[i+1] == 'green': |
| 46 | found_ivory_green = True |
| 47 | break |
| 48 | if not found_ivory_green: |
| 49 | continue |
| 50 | |
| 51 | # Constraint 2: The Englishman lives in the red house |
| 52 | red_index = color_perm.index('red') |
| 53 | if nationality_perm[red_index] != 'Englishman': |
| 54 | continue |
| 55 | |
| 56 | # Constraint 8: The person in the yellow house is a painter |
| 57 | # This will be checked later with hobbies |
| 58 | |
| 59 | for pet_perm in itertools.permutations(pets): |
| 60 | # Constraint 3: The Spaniard owns the dog |
| 61 | if nationality_perm[pet_perm.index('dog')] != 'Spaniard': |
| 62 | continue |
| 63 | |
| 64 | for drink_perm in itertools.permutations(drinks): |
| 65 | # Constraint 9: The person in the middle house drinks milk |
| 66 | if drink_perm[2] != 'milk': |
| 67 | continue |
| 68 | |
| 69 | # Constraint 4: The person in the green house drinks coffee |
| 70 | if drink_perm[color_perm.index('green')] != 'coffee': |
| 71 | continue |
| 72 | |
| 73 | # Constraint 5: The Ukrainian drinks tea |
| 74 | if nationality_perm[drink_perm.index('tea')] != 'Ukrainian': |
| 75 | continue |
| 76 | |
| 77 | for hobby_perm in itertools.permutations(hobbies): |
| 78 | # Constraint 7: The snail owner likes to go dancing |
| 79 | if hobby_perm[pet_perm.index('snail')] != 'dancing': |
| 80 | continue |
| 81 | |
| 82 | # Constraint 8: The person in the yellow house is a painter |
| 83 | if hobby_perm[color_perm.index('yellow')] != 'painting': |
| 84 | continue |
| 85 | |
| 86 | # Constraint 13: The person who plays football drinks orange juice |
| 87 | if hobby_perm[drink_perm.index('orange juice')] != 'football': |
| 88 | continue |
| 89 | |
| 90 | # Constraint 14: The Japanese person plays chess |
| 91 | if hobby_perm[nationality_perm.index('Japanese')] != 'chess': |
| 92 | continue |
| 93 | |
| 94 | # Constraint 11: The person who enjoys reading lives next to the person with the fox |
| 95 | reading_index = hobby_perm.index('reading') |
| 96 | fox_index = pet_perm.index('fox') |
| 97 | if abs(reading_index - fox_index) != 1: |
| 98 | continue |
| 99 | |
| 100 | # Constraint 12: The painter's house is next to the house with the horse |
| 101 | painting_index = hobby_perm.index('painting') |
| 102 | horse_index = pet_perm.index('horse') |
| 103 | if abs(painting_index - horse_index) != 1: |
| 104 | continue |
| 105 | |
| 106 | # If we reach here, we have a valid solution |
| 107 | houses = [] |
| 108 | for i in range(5): |
| 109 | house = { |
| 110 | 'nationality': nationality_perm[i], |
| 111 | 'color': color_perm[i], |
| 112 | 'pet': pet_perm[i], |
| 113 | 'drink': drink_perm[i], |
| 114 | 'hobby': hobby_perm[i] |
| 115 | } |
| 116 | houses.append(house) |
| 117 | return houses |
| 118 | |
| 119 | # This should not happen as the puzzle has a solution |
| 120 | return None |
| 121 | |
| 122 | # Handled Edge Cases: All constraints from the puzzle are implemented as checks in the solution process |