From ff1c438f582d7bb3ea90f37cf50ccd8f90c22f46 Mon Sep 17 00:00:00 2001 From: ZabihollahNamazi Date: Wed, 24 Jun 2026 16:11:52 +0100 Subject: [PATCH 1/3] lru cache done --- Sprint-2/implement_lru_cache/lru_cache.py | 68 +++++++++++++++++++++++ 1 file changed, 68 insertions(+) diff --git a/Sprint-2/implement_lru_cache/lru_cache.py b/Sprint-2/implement_lru_cache/lru_cache.py index e69de29b..00f4044d 100644 --- a/Sprint-2/implement_lru_cache/lru_cache.py +++ b/Sprint-2/implement_lru_cache/lru_cache.py @@ -0,0 +1,68 @@ +class CacheNode: + def __init__(self, key, value): + self.key = key + self.value = value + self.previous = None + self.next = None + +class LruCache: + def __init__(self, limit: int): + if limit <= 0: + raise ValueError("Cache limit must be greater than 0") + + self.limit = limit + self.lookup = {} + self.head = None + self.tail = None + + def _remove_node(self, node: CacheNode): + if node == self.head: + self.head = node.next + if node == self.tail: + self.tail = node.previous + + if node.previous is not None: + node.previous.next = node.next + if node.next is not None: + node.next.previous = node.previous + + node.next = None + node.previous = None + + def _move_to_head(self, node: CacheNode): + node.next = self.head + node.previous = None + + if self.head is None: + self.head = node + self.tail = node + else: + self.head.previous = node + self.head = node + + def get(self, key): + if key not in self.lookup: + return None + + node = self.lookup[key] + self._remove_node(node) + self._move_to_head(node) + return node.value + + def set(self, key, value) -> None: + if key in self.lookup: + node = self.lookup[key] + node.value = value + self._remove_node(node) + self._move_to_head(node) + else: + new_node = CacheNode(key, value) + + if len(self.lookup) >= self.limit: + oldest_node = self.tail + if oldest_node is not None: + del self.lookup[oldest_node.key] + self._remove_node(oldest_node) + + self._move_to_head(new_node) + self.lookup[key] = new_node \ No newline at end of file From 9e6a2729da25aa8a824edea2ba16406ecef4d478 Mon Sep 17 00:00:00 2001 From: ZabihollahNamazi Date: Sat, 27 Jun 2026 12:11:02 +0100 Subject: [PATCH 2/3] added the linkedlist class --- Sprint-2/implement_lru_cache/lru_cache.py | 51 ++++++++++++++++++++++- 1 file changed, 50 insertions(+), 1 deletion(-) diff --git a/Sprint-2/implement_lru_cache/lru_cache.py b/Sprint-2/implement_lru_cache/lru_cache.py index 00f4044d..2d9fb37b 100644 --- a/Sprint-2/implement_lru_cache/lru_cache.py +++ b/Sprint-2/implement_lru_cache/lru_cache.py @@ -3,7 +3,56 @@ def __init__(self, key, value): self.key = key self.value = value self.previous = None - self.next = None + self.next = None + + +class LinkedList: + def __init__(self): + self.head = None + self.tail = None + + def push_head(self, value) -> Node: + new_node = Node(value) + + if self.head is None: + self.head = new_node + self.tail = new_node + else: + new_node.next = self.head + self.head.previous = new_node + self.head = new_node + + return new_node + + def remove(self, node: Node) -> None: + if node is None: + return + + if node == self.head: + self.head = node.next + + if node == self.tail: + self.tail = node.previous + + if node.previous is not None: + node.previous.next = node.next + + if node.next is not None: + node.next.previous = node.previous + + node.next = None + node.previous = None + + def pop_tail(self): + if self.tail is None: + return None + + last_node = self.tail + value = last_node.value + + self.remove(last_node) + + return value class LruCache: def __init__(self, limit: int): From 3f3e5569d654ced480713a8357f5218f6b0f156c Mon Sep 17 00:00:00 2001 From: ZabihollahNamazi Date: Tue, 30 Jun 2026 17:31:34 +0100 Subject: [PATCH 3/3] update --- Sprint-2/implement_lru_cache/linked_list.py | 54 ++++++++++ Sprint-2/implement_lru_cache/lru_cache.py | 105 +++----------------- 2 files changed, 66 insertions(+), 93 deletions(-) create mode 100644 Sprint-2/implement_lru_cache/linked_list.py diff --git a/Sprint-2/implement_lru_cache/linked_list.py b/Sprint-2/implement_lru_cache/linked_list.py new file mode 100644 index 00000000..8974163d --- /dev/null +++ b/Sprint-2/implement_lru_cache/linked_list.py @@ -0,0 +1,54 @@ +class Node: + def __init__(self, key, value): + self.key = key + self.value = value + self.previous = None + self.next = None + + +class LinkedList: + def __init__(self): + self.head = None + self.tail = None + + def push_head(self, key, value) -> Node: + new_node = Node(key, value) + + if self.head is None: + self.head = new_node + self.tail = new_node + else: + new_node.next = self.head + self.head.previous = new_node + self.head = new_node + + return new_node + + def remove(self, node: Node) -> None: + if node is None: + return + + if node == self.head: + self.head = node.next + + if node == self.tail: + self.tail = node.previous + + if node.previous is not None: + node.previous.next = node.next + + if node.next is not None: + node.next.previous = node.previous + + node.next = None + node.previous = None + + def pop_tail(self) -> 'Node': + if self.tail is None: + return None + + last_node = self.tail + + self.remove(last_node) + + return last_node \ No newline at end of file diff --git a/Sprint-2/implement_lru_cache/lru_cache.py b/Sprint-2/implement_lru_cache/lru_cache.py index 2d9fb37b..c329ddab 100644 --- a/Sprint-2/implement_lru_cache/lru_cache.py +++ b/Sprint-2/implement_lru_cache/lru_cache.py @@ -1,58 +1,4 @@ -class CacheNode: - def __init__(self, key, value): - self.key = key - self.value = value - self.previous = None - self.next = None - - -class LinkedList: - def __init__(self): - self.head = None - self.tail = None - - def push_head(self, value) -> Node: - new_node = Node(value) - - if self.head is None: - self.head = new_node - self.tail = new_node - else: - new_node.next = self.head - self.head.previous = new_node - self.head = new_node - - return new_node - - def remove(self, node: Node) -> None: - if node is None: - return - - if node == self.head: - self.head = node.next - - if node == self.tail: - self.tail = node.previous - - if node.previous is not None: - node.previous.next = node.next - - if node.next is not None: - node.next.previous = node.previous - - node.next = None - node.previous = None - - def pop_tail(self): - if self.tail is None: - return None - - last_node = self.tail - value = last_node.value - - self.remove(last_node) - - return value +from linked_list import LinkedList, Node class LruCache: def __init__(self, limit: int): @@ -61,57 +7,30 @@ def __init__(self, limit: int): self.limit = limit self.lookup = {} - self.head = None - self.tail = None - - def _remove_node(self, node: CacheNode): - if node == self.head: - self.head = node.next - if node == self.tail: - self.tail = node.previous - - if node.previous is not None: - node.previous.next = node.next - if node.next is not None: - node.next.previous = node.previous - - node.next = None - node.previous = None - - def _move_to_head(self, node: CacheNode): - node.next = self.head - node.previous = None - - if self.head is None: - self.head = node - self.tail = node - else: - self.head.previous = node - self.head = node + self.list = LinkedList() def get(self, key): if key not in self.lookup: return None node = self.lookup[key] - self._remove_node(node) - self._move_to_head(node) - return node.value + value = node.value + + self.list.remove(node) + self.lookup[key] = self.list.push_head(key, value) + return value def set(self, key, value) -> None: if key in self.lookup: node = self.lookup[key] - node.value = value - self._remove_node(node) - self._move_to_head(node) + self.list.remove(node) + self.lookup[key] = self.list.push_head(key, value) else: - new_node = CacheNode(key, value) if len(self.lookup) >= self.limit: - oldest_node = self.tail + oldest_node = self.list.pop_tail() if oldest_node is not None: del self.lookup[oldest_node.key] - self._remove_node(oldest_node) + - self._move_to_head(new_node) - self.lookup[key] = new_node \ No newline at end of file + self.lookup[key] = self.list.push_head(key, value) \ No newline at end of file