📌 Current Implementation
The linked list currently uses two separate pointers (next, prev) for each node:
new_node = LinkedListNode(key, data,
links=['next', 'prev'],
addrs=[None, None])While this is clean and flexible (thanks to dynamic links and __slots__), it uses more memory per node, especially in large lists.
💡 Suggested Improvement
Use a single pointer both instead of next and prev to store the XOR of adjacent node addresses:
# XOR of previous and next node ids:
new_node.both = id(prev) ^ id(next)
This reduces memory consumption while still allowing bidirectional traversal.
Existing design (passing links dynamically and customizing slots) makes this refactor easier, as we only need:
links = ['both']
addrs = [0] # Initial XOR
✨ Benefits
Memory Efficient: Reduces pointer storage from 2 to 1 per node.
Demonstrates Advanced Technique: Shows how low-level pointer tricks can be adapted even in Python.
Backward Compatible: We could optionally provide a flag (mode='xor') to toggle between standard and XOR-based behavior.
⚠️ Notes / Considerations
Python doesn’t support pointer arithmetic directly — so we'll need to maintain a dictionary like:
self._nodes = {} # id(node): nodeto dereference id() values.
Need to handle None safely, using 0 as a placeholder in XOR ops.
🛠️ Task Outline
- Add
mode='xor' option to the Linked List class.
- Create a new
LinkedListNode with links=['both'] and store XOR of ids.
- Maintain an internal
id_to_node dictionary to simulate pointer access.
- Refactor
insert_after, traverse, and other methods accordingly.
- Add unit tests comparing standard and XOR list behavior.
📌 Current Implementation
The linked list currently uses two separate pointers (
next,prev) for each node:While this is clean and flexible (thanks to dynamic links and
__slots__), it uses more memory per node, especially in large lists.💡 Suggested Improvement
Use a single pointer both instead of next and prev to store the XOR of adjacent node addresses:
This reduces memory consumption while still allowing bidirectional traversal.
Existing design (passing links dynamically and customizing slots) makes this refactor easier, as we only need:
✨ Benefits
Memory Efficient: Reduces pointer storage from 2 to 1 per node.
Demonstrates Advanced Technique: Shows how low-level pointer tricks can be adapted even in Python.
Backward Compatible: We could optionally provide a flag (mode='xor') to toggle between standard and XOR-based behavior.
Python doesn’t support pointer arithmetic directly — so we'll need to maintain a dictionary like:
to dereference id() values.
Need to handle None safely, using 0 as a placeholder in XOR ops.
🛠️ Task Outline
mode='xor'option to the Linked List class.LinkedListNodewithlinks=['both']and store XOR of ids.id_to_nodedictionary to simulate pointer access.insert_after, traverse, and other methods accordingly.