refactor: rename interfaces with I prefix and remove Impl suffix

- Stack → IStack, SinglyLinkedList → ISinglyLinkedList, DoublyLinkedList → IDoublyLinkedList
- SinglyLinkedListImpl → SinglyLinkedList, DoublyLinkedListImpl → DoublyLinkedList
- Fix stack test imports (stacks → stack)
- Update README accordingly

Author: AzizAlievDevelopment

README.md

@@ -33,20 +33,20 @@ ms.get_min()  # 3
 
 | Implementation | Description |
 |---|---|
-| `SinglyLinkedListImpl` | Singly linked list with O(1) push/pop at the head. |
-| `DoublyLinkedListImpl` | Doubly linked list with O(1) push/pop at both head and tail. |
+| `SinglyLinkedList` | Singly linked list with O(1) push/pop at the head. |
+| `DoublyLinkedList` | Doubly linked list with O(1) push/pop at both head and tail. |
 
 ```python
-from data_structures.linked_list import SinglyLinkedListImpl, DoublyLinkedListImpl
+from data_structures.linked_list import SinglyLinkedList, DoublyLinkedList
 
-sll = SinglyLinkedListImpl()
+sll = SinglyLinkedList()
 sll.push_front(1)
 sll.push_front(2)
 sll.peek_front()  # 2
 sll.pop_front()   # 2
 list(sll)         # [1]
 
-dll = DoublyLinkedListImpl()
+dll = DoublyLinkedList()
 dll.push_front(1)
 dll.push_back(2)
 dll.push_back(3)
@@ -80,8 +80,8 @@ data_structures/
     min_stack.py     # MinStack implementation
   linked_list/
     base.py                # SinglyLinkedList & DoublyLinkedList ABCs
-    singly_linked_list.py  # SinglyLinkedListImpl
-    doubly_linked_list.py  # DoublyLinkedListImpl
+    singly_linked_list.py  # SinglyLinkedList
+    doubly_linked_list.py  # DoublyLinkedList
 tests/
   test_stacks.py           # pytest suite for stack implementations
   test_linked_lists.py     # pytest suite for linked list implementations

data_structures/linked_list/__init__.py

@@ -1,11 +1,11 @@
-from .base import DoublyLinkedList, LinkedListEmptyError, SinglyLinkedList
-from .doubly_linked_list import DoublyLinkedListImpl
-from .singly_linked_list import SinglyLinkedListImpl
+from .base import IDoublyLinkedList, ISinglyLinkedList, LinkedListEmptyError
+from .doubly_linked_list import DoublyLinkedList
+from .singly_linked_list import SinglyLinkedList
 
 __all__ = [
+    "IDoublyLinkedList",
     "DoublyLinkedList",
-    "DoublyLinkedListImpl",
+    "ISinglyLinkedList",
     "LinkedListEmptyError",
     "SinglyLinkedList",
-    "SinglyLinkedListImpl",
 ]

data_structures/linked_list/base.py

@@ -9,7 +9,7 @@ def __init__(self) -> None:
         super().__init__("Linked list is empty")
 
 
-class SinglyLinkedList[T](ABC):
+class ISinglyLinkedList[T](ABC):
     """Abstract Singly Linked List interface.
 
     Each node holds a reference only to the *next* node.
@@ -40,11 +40,11 @@ def __iter__(self) -> Iterator[T]:
         """Iterate over all elements from head to tail."""
 
 
-class DoublyLinkedList[T](SinglyLinkedList[T]):
+class IDoublyLinkedList[T](ISinglyLinkedList[T]):
     """Abstract Doubly Linked List interface.
 
     Each node holds references to both *next* and *prev* nodes.
-    Adds O(1) tail operations on top of ``SinglyLinkedList``.
+    Adds O(1) tail operations on top of ``ISinglyLinkedList``.
     """
 
     @abstractmethod

data_structures/linked_list/doubly_linked_list.py

@@ -1,6 +1,6 @@
 from typing import Iterator
 
-from .base import DoublyLinkedList, LinkedListEmptyError
+from .base import IDoublyLinkedList, LinkedListEmptyError
 
 
 class _Node[T]:
@@ -17,7 +17,7 @@ def __init__(
         self.next = next
 
 
-class DoublyLinkedListImpl[T](DoublyLinkedList[T]):
+class DoublyLinkedList[T](IDoublyLinkedList[T]):
     """Doubly linked list backed by ``_Node`` objects."""
 
     def __init__(self) -> None:

data_structures/linked_list/singly_linked_list.py

@@ -1,6 +1,6 @@
 from typing import Iterator
 
-from .base import LinkedListEmptyError, SinglyLinkedList
+from .base import ISinglyLinkedList, LinkedListEmptyError
 
 
 class _Node[T]:
@@ -11,7 +11,7 @@ def __init__(self, value: T, next: "_Node[T] | None" = None) -> None:
         self.next = next
 
 
-class SinglyLinkedListImpl[T](SinglyLinkedList[T]):
+class SinglyLinkedList[T](ISinglyLinkedList[T]):
     """Singly linked list backed by ``_Node`` objects."""
 
     def __init__(self) -> None:

data_structures/stack/array_stack.py

@@ -1,7 +1,7 @@
-from .base import Stack, StackEmptyError
+from .base import IStack, StackEmptyError
 
 
-class ArrayStack[T](Stack):
+class ArrayStack[T](IStack):
     """Stack backed by a dynamic array (``list``)."""
 
     def __init__(self) -> None:

data_structures/stack/base.py

@@ -8,7 +8,7 @@ def __init__(self) -> None:
         super().__init__("Stack is empty")
 
 
-class Stack[T](ABC):
+class IStack[T](ABC):
     """Abstract Stack interface (LIFO - Last In First Out).
 
     >>> s = ArrayStack()

tests/test_linked_lists.py

@@ -1,16 +1,16 @@
 import pytest
 
 from data_structures.linked_list import (
-    DoublyLinkedListImpl,
+    DoublyLinkedList,
     LinkedListEmptyError,
-    SinglyLinkedListImpl,
+    SinglyLinkedList,
 )
 
 
 # ── Shared tests (both singly and doubly) ────────────────────────────
 
 
-@pytest.fixture(params=[SinglyLinkedListImpl, DoublyLinkedListImpl])
+@pytest.fixture(params=[SinglyLinkedList, DoublyLinkedList])
 def ll(request):
     return request.param()
 
@@ -87,7 +87,7 @@ def test_push_pop_until_empty(ll):
 
 @pytest.fixture
 def dll():
-    return DoublyLinkedListImpl()
+    return DoublyLinkedList()
 
 
 def test_push_back_and_peek_back(dll):

tests/test_stacks.py

@@ -1,8 +1,8 @@
 import pytest
 
-from data_structures.stacks.array_stack import ArrayStack
-from data_structures.stacks.base import StackEmptyError
-from data_structures.stacks.min_stack import MinStack
+from data_structures.stack.array_stack import ArrayStack
+from data_structures.stack.base import StackEmptyError
+from data_structures.stack.min_stack import MinStack
 
 
 @pytest.fixture(params=[ArrayStack, MinStack])