一、OrderedDict
1 class LRUCache: 2 def __init__(self, capacity: int): 3 from collections import OrderedDict 4 self.cap = capacity 5 self.dic = OrderedDict() 6 def get(self, key: int) -> int: 7 if key not in self.dic: 8 return -1 9 self.dic.move_to_end(key) 10 return self.dic[key] 11 12 def put(self, key: int, value: int) -> None: 13 if key in self.dic: 14 self.dic.move_to_end(key) 15 self.dic[key] = value 16 if len(self.dic) > self.cap: 17 self.dic.popitem(last=False) 18 19 # Your LRUCache object will be instantiated and called as such: 20 # obj = LRUCache(capacity) 21 # param_1 = obj.get(key) 22 # obj.put(key,value)
二、双向链表+dict
1 class DLinkedNode(): 2 def __init__(self, key=0, value=0): 3 self.key = key 4 self.value = value 5 self.prev = None 6 self.next = None 7 8 class LRUCache: 9 def __init__(self, capacity: int): 10 self.cache = {} 11 self.size = 0 12 self.capacity = capacity 13 self.head, self.tail = DLinkedNode(), DLinkedNode() 14 15 self.head.next = self.tail 16 self.tail.prev = self.head 17 18 def _add_node(self, node): 19 node.prev = self.head 20 node.next = self.head.next 21 22 self.head.next.prev = node 23 self.head.next = node 24 25 def _remove_node(self, node): 26 prev = node.prev 27 new = node.next 28 29 prev.next = new 30 new.prev = prev 31 32 def _move_to_head(self, node): 33 self._remove_node(node) 34 self._add_node(node) 35 36 def _pop_tail(self): 37 res = self.tail.prev 38 self._remove_node(res) 39 return res 40 41 def get(self, key: int) -> int: 42 node = self.cache.get(key, None) 43 if not node: 44 return -1 45 self._move_to_head(node) 46 return node.value 47 48 def put(self, key: int, value: int) -> None: 49 node = self.cache.get(key) 50 51 if not node: 52 newNode = DLinkedNode(key, value) 53 54 self.cache[key] = newNode 55 self._add_node(newNode) 56 57 self.size += 1 58 59 if self.size > self.capacity: 60 tail = self._pop_tail() 61 del self.cache[tail.key] 62 self.size -= 1 63 else: 64 node.value = value 65 self._move_to_head(node) 66 67 68 69 70 # Your LRUCache object will be instantiated and called as such: 71 # obj = LRUCache(capacity) 72 # param_1 = obj.get(key) 73 # obj.put(key,value)