Sheffield | 25-SDC-Nov | Sheida Shabankari | Sprint 2 | Implement LRU cache in python#105
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sheida-shab wants to merge 6 commits intoCodeYourFuture:mainfrom
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Sheffield | 25-SDC-Nov | Sheida Shabankari | Sprint 2 | Implement LRU cache in python#105sheida-shab wants to merge 6 commits intoCodeYourFuture:mainfrom
sheida-shab wants to merge 6 commits intoCodeYourFuture:mainfrom
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sheida-shab
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cjyuan
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Why not simply import or subclass the Double Linked List you implemented in the other exercise (to practice code reuse)?
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Alternatively, you can explore using
OrderedDictwithinLruCacheto maintain order.
Could you improve your LruCache implementation using one of these approaches?
| raise ValueError("limit must be greater than zero") | ||
| self.limit=limit | ||
| self.map={} | ||
| self.List=LinkedList() |
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Why start the name the property List with an uppercase L?
| def push_head(self,node=None,key=None,value=None) -> Node: | ||
| """ | ||
| Adds a node to the head of the list. | ||
| If 'node' is provided, it is moved to the head. |
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Moving a node to the front does not seem like a normal behavior expected from the "push head" operation.
You could consider implementing a helper function or just have the caller explicitly
- remove the node to be moved, and
- add that node to the front of the list
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PR Summary :
Implement LRU Cache with O(1) get/set operations
Description:
This PR adds a fully functional LRU (Least Recently Used) cache in Python. The implementation includes:
Node class: Represents a key-value pair with pointers to previous and next nodes.
Doubly linked list: Maintains the order of nodes for LRU eviction in O(1) time.
push_head: Moves or adds a node to the head (most recently used).
pop_tail: Removes and returns the tail node (least recently used).
remove: Removes a specific node from the list.
LruCache class: Provides the cache interface.
get(key): Retrieves a value by key and marks the node as most recently used.
set(key, value): Adds or updates a key-value pair; evicts the least recently used node if the cache exceeds its limit.
Handles invalid cache limits by raising ValueError.
Each operation (get and set) has O(1) worst-case time complexity.
Testing:
Unit tests cover cache limit enforcement, eviction order, and get/set functionality.