LRU cache

/*
OrderedDict whill maintain the actual key and value and also the order.
Once an element is accessed, push to the end and end will be considered the Recently used and start will be least used.
same goes for put also.
*/

from collections import OrderedDict
class LRUCache:
    def __init__(self, capacity: int):
        self.capacity = capacity
        self.cache = OrderedDict()  # maintains insertion order

    def get(self, key: int) -> int:
        if key not in self.cache:
            return -1
        self.cache.move_to_end(key)  # mark as most recently used → O(1)
        return self.cache[key]

    def put(self, key: int, value: int) -> None:
        if key in self.cache:
            self.cache.move_to_end(key)  # mark as most recently used → O(1)
        self.cache[key] = value
        if len(self.cache) > self.capacity:
            self.cache.popitem(last=False)  # remove least recently used → O(1)