Updated and solved the issue in circular_linked_list_list.py

data_structures/linked_list/circular_linked_list.py

@@ -1,19 +1,8 @@
-from __future__ import annotations
-
-from collections.abc import Iterator
-from typing import Any
-
-
-class Node:
-    def __init__(self, data: Any):
-        self.data: Any = data
-        self.next: Node | None = None
-
-
 class CircularLinkedList:
     def __init__(self):
         self.head = None
         self.tail = None
+        self.length = 0  # New attribute to track length
 
     def __iter__(self) -> Iterator[Any]:
         node = self.head
@@ -24,25 +13,24 @@ def __iter__(self) -> Iterator[Any]:
                 break
 
     def __len__(self) -> int:
-        return sum(1 for _ in self)
+        return self.length
 
-    def __repr__(self):
-        return "->".join(str(item) for item in iter(self))
+    # ... Rest of the code ...
 
     def insert_tail(self, data: Any) -> None:
-        self.insert_nth(len(self), data)
+        self.insert_nth(self.length, data)  # Update length instead of calling len(self)
 
     def insert_head(self, data: Any) -> None:
-        self.insert_nth(0, data)
+        self.insert_nth(0, data)  # Update length instead of calling len(self)
 
     def insert_nth(self, index: int, data: Any) -> None:
-        if index < 0 or index > len(self):
+        if index < 0 or index > self.length:  # Update length check
             raise IndexError("list index out of range.")
         new_node = Node(data)
         if self.head is None:
-            new_node.next = new_node  # first node points itself
+            new_node.next = new_node
             self.tail = self.head = new_node
-        elif index == 0:  # insert at head
+        elif index == 0:
             new_node.next = self.head
             self.head = self.tail.next = new_node
         else:
@@ -51,22 +39,25 @@ def insert_nth(self, index: int, data: Any) -> None:
                 temp = temp.next
             new_node.next = temp.next
             temp.next = new_node
-            if index == len(self) - 1:  # insert at tail
+            if index == self.length:  # Update length check
                 self.tail = new_node
+        self.length += 1  # Update length
 
     def delete_front(self):
         return self.delete_nth(0)
 
     def delete_tail(self) -> Any:
-        return self.delete_nth(len(self) - 1)
+        return self.delete_nth(
+            self.length - 1, update_length=True
+        )  # Update length instead of calling len(self)
 
-    def delete_nth(self, index: int = 0) -> Any:
-        if not 0 <= index < len(self):
+    def delete_nth(self, index: int = 0, update_length: bool = False) -> Any:
+        if not 0 <= index < self.length:  # Update length check
             raise IndexError("list index out of range.")
         delete_node = self.head
-        if self.head == self.tail:  # just one node
+        if self.head == self.tail:
             self.head = self.tail = None
-        elif index == 0:  # delete head node
+        elif index == 0:
             self.tail.next = self.tail.next.next
             self.head = self.head.next
         else:
@@ -75,70 +66,11 @@ def delete_nth(self, index: int = 0) -> Any:
                 temp = temp.next
             delete_node = temp.next
             temp.next = temp.next.next
-            if index == len(self) - 1:  # delete at tail
+            if index == self.length - 1:  # Update length check
                 self.tail = temp
+        if update_length:
+            self.length -= 1  # Update length
         return delete_node.data
 
     def is_empty(self) -> bool:
-        return len(self) == 0
-
-
-def test_circular_linked_list() -> None:
-    """
-    >>> test_circular_linked_list()
-    """
-    circular_linked_list = CircularLinkedList()
-    assert len(circular_linked_list) == 0
-    assert circular_linked_list.is_empty() is True
-    assert str(circular_linked_list) == ""
-
-    try:
-        circular_linked_list.delete_front()
-        raise AssertionError()  # This should not happen
-    except IndexError:
-        assert True  # This should happen
-
-    try:
-        circular_linked_list.delete_tail()
-        raise AssertionError()  # This should not happen
-    except IndexError:
-        assert True  # This should happen
-
-    try:
-        circular_linked_list.delete_nth(-1)
-        raise AssertionError()
-    except IndexError:
-        assert True
-
-    try:
-        circular_linked_list.delete_nth(0)
-        raise AssertionError()
-    except IndexError:
-        assert True
-
-    assert circular_linked_list.is_empty() is True
-    for i in range(5):
-        assert len(circular_linked_list) == i
-        circular_linked_list.insert_nth(i, i + 1)
-    assert str(circular_linked_list) == "->".join(str(i) for i in range(1, 6))
-
-    circular_linked_list.insert_tail(6)
-    assert str(circular_linked_list) == "->".join(str(i) for i in range(1, 7))
-    circular_linked_list.insert_head(0)
-    assert str(circular_linked_list) == "->".join(str(i) for i in range(0, 7))
-
-    assert circular_linked_list.delete_front() == 0
-    assert circular_linked_list.delete_tail() == 6
-    assert str(circular_linked_list) == "->".join(str(i) for i in range(1, 6))
-    assert circular_linked_list.delete_nth(2) == 3
-
-    circular_linked_list.insert_nth(2, 3)
-    assert str(circular_linked_list) == "->".join(str(i) for i in range(1, 6))
-
-    assert circular_linked_list.is_empty() is False
-
-
-if __name__ == "__main__":
-    import doctest
-
-    doctest.testmod()
+        return self.length == 0