|
| 1 | +from stack import Stack |
| 2 | + |
| 3 | + |
| 4 | +class TowerOfHanoi: |
| 5 | + class __EmptySourceRodError(Exception): |
| 6 | + def __str__(self) -> str: |
| 7 | + return "Number of disks in the source rod cannot be less than 1." |
| 8 | + |
| 9 | + class __AlreadySolvedError(Exception): |
| 10 | + def __str__(self) -> str: |
| 11 | + return "The puzzle has already been solved. Please reset the puzzle before adding more disks." |
| 12 | + |
| 13 | + def __init__(self) -> None: |
| 14 | + self.__source_rod: Stack = Stack() |
| 15 | + self.__auxiliary_rod: Stack = Stack() |
| 16 | + self.__destination_rod: Stack = Stack() |
| 17 | + self.__no_of_disks: int = 0 |
| 18 | + self.__solved: bool = False |
| 19 | + |
| 20 | + def solved(self) -> bool: |
| 21 | + return self.__solved |
| 22 | + |
| 23 | + def add_disks(self, no_of_disks: int) -> None: |
| 24 | + if not self.__solved: |
| 25 | + self.__no_of_disks += no_of_disks |
| 26 | + self.__source_rod.empty_stack() |
| 27 | + for disk_id in reversed(range(1, self.__no_of_disks + 1)): |
| 28 | + self.__source_rod.push(f'disk {disk_id}') |
| 29 | + else: |
| 30 | + raise self.__AlreadySolvedError |
| 31 | + |
| 32 | + def display(self) -> None: |
| 33 | + print(self.__source_rod, end=' - ') |
| 34 | + print(self.__auxiliary_rod, end=' - ') |
| 35 | + print(self.__destination_rod) |
| 36 | + |
| 37 | + def __tower_of_hanoi(self, disks: int, source: Stack, destination: Stack, auxiliary: Stack) -> None: |
| 38 | + if disks == 1: |
| 39 | + source.pop() |
| 40 | + destination.push('disk 1') |
| 41 | + elif disks > 1: |
| 42 | + self.__tower_of_hanoi(disks - 1, source=source, destination=auxiliary, auxiliary=destination) |
| 43 | + source.pop() |
| 44 | + destination.push(f'disk {disks}') |
| 45 | + self.__tower_of_hanoi(disks - 1, source=auxiliary, destination=destination, auxiliary=source) |
| 46 | + |
| 47 | + def start(self) -> None: |
| 48 | + if self.__no_of_disks < 1: |
| 49 | + raise self.__EmptySourceRodError |
| 50 | + self.__tower_of_hanoi(len(self.__source_rod), self.__source_rod, self.__destination_rod, self.__auxiliary_rod) |
| 51 | + self.__solved = True |
| 52 | + |
| 53 | + def reset(self) -> None: |
| 54 | + self.__source_rod.empty_stack() |
| 55 | + self.__auxiliary_rod.empty_stack() |
| 56 | + self.__destination_rod.empty_stack() |
| 57 | + self.__no_of_disks = 0 |
| 58 | + self.__solved = False |
| 59 | + |
| 60 | + |
| 61 | +if __name__ == '__main__': |
| 62 | + tower = TowerOfHanoi() |
| 63 | + tower.add_disks(int(input('Enter the number of the disks : '))) |
| 64 | + print("Adding 2 more disks") |
| 65 | + tower.add_disks(2) |
| 66 | + print("Unsolved") |
| 67 | + tower.display() |
| 68 | + tower.start() |
| 69 | + print("Solved") |
| 70 | + tower.display() |
| 71 | + tower.reset() |
| 72 | + print("Reset") |
| 73 | + tower.display() |
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