Added tower_of_hanoi_stack.py

Author: VarunS2002

tower_of_hanoi_stack.py

@@ -0,0 +1,73 @@
+from stack import Stack
+
+
+class TowerOfHanoi:
+    class __EmptySourceRodError(Exception):
+        def __str__(self) -> str:
+            return "Number of disks in the source rod cannot be less than 1."
+
+    class __AlreadySolvedError(Exception):
+        def __str__(self) -> str:
+            return "The puzzle has already been solved. Please reset the puzzle before adding more disks."
+
+    def __init__(self) -> None:
+        self.__source_rod: Stack = Stack()
+        self.__auxiliary_rod: Stack = Stack()
+        self.__destination_rod: Stack = Stack()
+        self.__no_of_disks: int = 0
+        self.__solved: bool = False
+
+    def solved(self) -> bool:
+        return self.__solved
+
+    def add_disks(self, no_of_disks: int) -> None:
+        if not self.__solved:
+            self.__no_of_disks += no_of_disks
+            self.__source_rod.empty_stack()
+            for disk_id in reversed(range(1, self.__no_of_disks + 1)):
+                self.__source_rod.push(f'disk {disk_id}')
+        else:
+            raise self.__AlreadySolvedError
+
+    def display(self) -> None:
+        print(self.__source_rod, end=' - ')
+        print(self.__auxiliary_rod, end=' - ')
+        print(self.__destination_rod)
+
+    def __tower_of_hanoi(self, disks: int, source: Stack, destination: Stack, auxiliary: Stack) -> None:
+        if disks == 1:
+            source.pop()
+            destination.push('disk 1')
+        elif disks > 1:
+            self.__tower_of_hanoi(disks - 1, source=source, destination=auxiliary, auxiliary=destination)
+            source.pop()
+            destination.push(f'disk {disks}')
+            self.__tower_of_hanoi(disks - 1, source=auxiliary, destination=destination, auxiliary=source)
+
+    def start(self) -> None:
+        if self.__no_of_disks < 1:
+            raise self.__EmptySourceRodError
+        self.__tower_of_hanoi(len(self.__source_rod), self.__source_rod, self.__destination_rod, self.__auxiliary_rod)
+        self.__solved = True
+
+    def reset(self) -> None:
+        self.__source_rod.empty_stack()
+        self.__auxiliary_rod.empty_stack()
+        self.__destination_rod.empty_stack()
+        self.__no_of_disks = 0
+        self.__solved = False
+
+
+if __name__ == '__main__':
+    tower = TowerOfHanoi()
+    tower.add_disks(int(input('Enter the number of the disks : ')))
+    print("Adding 2 more disks")
+    tower.add_disks(2)
+    print("Unsolved")
+    tower.display()
+    tower.start()
+    print("Solved")
+    tower.display()
+    tower.reset()
+    print("Reset")
+    tower.display()