import time
from collections import OrderedDict


class AlexaDeduplicator:

    MAX_ENTRIES = 500
    TTL_SECONDS = 300

    def __init__(self):
        self._cache: OrderedDict[str, float] = OrderedDict()

    def is_duplicate(self, request_id: str) -> bool:
        if not request_id:
            return False

        now = time.time()

        while self._cache:
            oldest_key, oldest_time = next(iter(self._cache.items()))
            if now - oldest_time > self.TTL_SECONDS:
                self._cache.popitem(last=False)
            else:
                break

        if request_id in self._cache:
            return True

        self._cache[request_id] = now

        while len(self._cache) > self.MAX_ENTRIES:
            self._cache.popitem(last=False)

        return False