import LRUCache
import time


def expensive_query(query):
    print(f"Running query: {query}")
    time.sleep(2)  # Simulate delay
    return f"Result for '{query}'"

class QueryEngine:
    def __init__(self, cache_size=5):
        self.cache = LRUCache(cache_size)

    def run_query(self, query):
        cached = self.cache.get(query)
        if cached != -1:
            print(f"Cache hit for: {query}")
            return cached
        result = expensive_query(query)
        self.cache.put(query, result)
        return result
    
    
engine = QueryEngine()

print(engine.run_query("SELECT * FROM users"))
print(engine.run_query("SELECT * FROM orders"))
print(engine.run_query("SELECT * FROM users"))  # Cached!
print(engine.run_query("SELECT * FROM products"))
print(engine.run_query("SELECT * FROM inventory"))
print(engine.run_query("SELECT * FROM orders"))  # Might be evicted