# Your LRUCache object will be instantiated and called as such:
# obj = LRUCache(capacity)
# param_1 = obj.get(key)
# obj.put(key,value)
from collections import OrderedDict
class LRUCache:
    '''
    Time Complexity: O(1)
    Space Complexity: O(n)
    where, n is the capacity of cache
    Solved in 10 mins the second time, referred OrderedDict syntax!
    '''
    def __init__(self, capacity: int):
        self.q = OrderedDict()
        self.size = capacity

    def get(self, key: int) -> int:
        if key not in self.q:
            return -1
        self.q.move_to_end(key, last=False)
        return self.q[key]
        
    def put(self, key: int, value: int) -> None:
        if len(self.q) >= self.size and key not in self.q:
            self.q.popitem(last=True)
        self.q[key] = value
        self.q.move_to_end(key, last=False)

# Your LRUCache object will be instantiated and called as such:
# obj = LRUCache(capacity)
# param_1 = obj.get(key)
# obj.put(key,value)
class DoubleNode:
    def __init__(self, key=None, value=None):
        self.key = key
        self.value = value
        self.left = None
        self.right = None

class LRUCache:
    '''
    Time Complexity: O(1) for both get and put operations.
    Space Complexity: O(capacity), where capacity is the maximum number of items that can be stored in the cache.
    This is the more traditional approach using Doubly Linked List and Hash Map.
    NOTE: This approach is not recommended, took you almost 1 hour to implement it correctly, stick to the OrderedDict approach.
    '''

    def __init__(self, capacity: int):
        self.capacity = capacity
        self.cache = {}

        self.head = DoubleNode()
        self.tail = DoubleNode()
        self.head.right = self.tail
        self.tail.left = self.head

    def _remove(self, node):
        node.left.right = node.right
        node.right.left = node.left

    def _add_to_head(self, node):
        node.left = self.head
        node.right = self.head.right
        self.head.right.left = node
        self.head.right = node

    def get(self, key: int) -> int:
        if key not in self.cache:
            return -1

        node = self.cache[key]
        self._remove(node)
        self._add_to_head(node)
        return node.value

    def put(self, key: int, value: int) -> None:
        if key in self.cache:
            node = self.cache[key]
            node.value = value
            self._remove(node)
            self._add_to_head(node)
            return

        node = DoubleNode(key, value)
        self.cache[key] = node
        self._add_to_head(node)

        if len(self.cache) > self.capacity:
            lru = self.tail.left
            self._remove(lru)
            del self.cache[lru.key]