class Node:
key = None
value = None
pre = None
next = None
def __init__(self, key, value):
self.key = key
self.value = value
class LRUCache:
capacity = 0
mapping = {}
head = None
end = None
def __init__(self, capacity):
self.capacity = capacity
def set(self, key, value):
if key in self.mapping:
oldNode = self.mapping[key]
oldNode.value = value
self.remove(oldNode)
self.set_head(oldNode)
else:
node = Node(key, value)
if len(self.mapping) >= self.capacity:
self.mapping.pop(self.end.key)
self.remove(self.end)
self.set_head(node)
else:
self.set_head(node)
self.mapping[key] = node
def set_head(self, n):
n.next = self.head
n.pre = None
if self.head:
self.head.pre = n
self.head = n
if not self.end:
self.end = self.head
def remove(self, n):
if n.pre:
n.pre.next = n.next
else:
self.head = n.next
if n.next:
n.next.pre = n.pre
else:
self.end = n.pre
def get_all_keys(self):
tmp_node = None
if self.head:
tmp_node = self.head
temp = "<{0},{1}>"
result = ""
while tmp_node:
tmp = temp.format(tmp_node.key, tmp_node.value)
result += tmp
result += " -> "
tmp_node = tmp_node.next
tmp = temp.format(None, None)
result += tmp
print(result)
def get(self, key):
if key in self.mapping:
node = self.mapping[key]
self.remove(node)
self.set_head(node)
return node.value
else:
return -1
if __name__ == '__main__':
cache = LRUCache(100)
cache.set('a', '1')
cache.set('b', '2')
cache.set('c', 3)
cache.set('d', 4)
cache.get_all_keys()
cache.set('a', 5)
cache.get_all_keys()
cache.get('c')
cache.get_all_keys()
