Stack implemented with a dynamic array. Examples: >>> s = ArrayStack() >>> s.push(1) >>> s.pop() 1
| 56 | |
| 57 | |
| 58 | class ArrayStack(AbstractStack): |
| 59 | """Stack implemented with a dynamic array. |
| 60 | |
| 61 | Examples: |
| 62 | >>> s = ArrayStack() |
| 63 | >>> s.push(1) |
| 64 | >>> s.pop() |
| 65 | 1 |
| 66 | """ |
| 67 | |
| 68 | def __init__(self, size: int = 10) -> None: |
| 69 | """Initialize with a fixed-size array. |
| 70 | |
| 71 | Args: |
| 72 | size: Initial capacity of the underlying array. |
| 73 | """ |
| 74 | super().__init__() |
| 75 | self._array: list[object | None] = [None] * size |
| 76 | |
| 77 | def __iter__(self) -> Iterator[object]: |
| 78 | probe = self._top |
| 79 | while True: |
| 80 | if probe == -1: |
| 81 | return |
| 82 | yield self._array[probe] |
| 83 | probe -= 1 |
| 84 | |
| 85 | def push(self, value: object) -> None: |
| 86 | """Push a value onto the stack. |
| 87 | |
| 88 | Args: |
| 89 | value: The value to push. |
| 90 | """ |
| 91 | self._top += 1 |
| 92 | if self._top == len(self._array): |
| 93 | self._expand() |
| 94 | self._array[self._top] = value |
| 95 | |
| 96 | def pop(self) -> object: |
| 97 | """Remove and return the top element. |
| 98 | |
| 99 | Returns: |
| 100 | The top element. |
| 101 | |
| 102 | Raises: |
| 103 | IndexError: If the stack is empty. |
| 104 | """ |
| 105 | if self.is_empty(): |
| 106 | raise IndexError("Stack is empty") |
| 107 | value = self._array[self._top] |
| 108 | self._top -= 1 |
| 109 | return value |
| 110 | |
| 111 | def peek(self) -> object: |
| 112 | """Return the top element without removing it. |
| 113 | |
| 114 | Returns: |
| 115 | The top element. |
no outgoing calls