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lrucache.py
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lrucache.py
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import collections
class lrucache:
def __init__(self, capacity):
self.deque = collections.deque([])
self.dic = {}
self.capacity = capacity
def get(self, key):
if key not in self.dic:
return -1
self.deque.remove(key)
self.deque.append(key)
return self.dic[key]
def set(self, key, value):
if key in self.dic:
self.deque.remove(key)
elif len(self.dic) == self.capacity:
v = self.deque.popleft() # remove the Least Recently Used element
self.dic.pop(v)
self.deque.append(key)
self.dic[key] = value
class DoubleLinkedNode:
def __init__(self, k, v):
self.key = k
self.value = v
self.prev = None
self.next = None
class LRUCache:
def __init__(self, capacity):
self.capacity = capacity
self.dic = {}
self.head = DoubleLinkedNode(None, None)
self.tail = DoubleLinkedNode(None, None)
self.head.next = self.tail
self.tail.prev = self.head
def get(self, key):
if key not in self.dic:
return -1
res = self.dic[key]
self._remove(res)
self._insert(res)
return res.value
def put(self, key, value):
if key in self.dic:
self._remove(self.dic[key])
del self.dic[key]
elif len(self.dic) >= self.capacity:
del self.dic[self.tail.prev.key]
self._remove(self.tail.prev)
new_node = DoubleLinkedNode(key, value)
self.dic[key] = new_node
self._insert(new_node)
def _insert(self, node):
node.next = self.head.next
node.prev = self.head
self.head.next.prev = node
self.head.next = node
def _remove(self, node):
prev = node.prev
nxt = node.next
prev.next = nxt
nxt.prev = prev