Remove Method in a Doubly Linked List

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Remove Method in a Doubly Linked List

The remove method allows you to delete a node at a specific index in a doubly linked list.
It handles removing nodes from the beginning, the end, or anywhere in the middle of the list.

🧩 Steps to Remove a Node

Check for invalid index:
- If index < 0 or index ≥ length, return None.
Remove at the ends:
- If index == 0: Use the pop_first method.
- If index == length - 1: Use the pop method.
Remove from the middle:
- Use a temporary variable to locate the node to remove:
  
  temp = self.get(index)
- Redirect the prev and next pointers of surrounding nodes:
  
  temp.next.prev = temp.prev temp.prev.next = temp.next
- Disconnect the node completely:
  
  temp.next = None temp.prev = None
- Decrement the length by 1.
Return:
- Return the removed node (temp) so you have access to it if needed.

💻 Code Example

class DoublyLinkedList:

def remove(self, index):

if index < 0 or index >= self.length:

return None

if index == 0:

return self.pop_first()

if index == self.length – 1:

return self.pop()

temp = self.get(index)

temp.next.prev = temp.prev

temp.prev.next = temp.next

temp.next = None

temp.prev = None

self.length -= 1

return temp

🧪 Example Run

Output:

✅ Key Takeaways

Step	Description
1	Validate index (0 ≤ index < length)
2	Handle edge cases with `pop_first` and `pop`
3	Redirect pointers of `prev` and `next` for middle nodes
4	Disconnect removed node to avoid memory leaks
5	Update `length` property
6	Return the removed node

Time Complexity: O(n) for removing a middle node (traversal using get), O(1) for head or tail.
Pointer Management: Always update four pointers in the middle to maintain list integrity.