Cuckoo Hashing
Cuckoo hashing is a collision resolution scheme for hash tables that guarantees constant worst-case lookup time of O(1) by using two or more hash functions and dynamically reallocating keys when collisions occur. It works by maintaining multiple hash tables and moving keys between them when necessary, ensuring each key has a designated spot in at least one table. This approach is particularly useful in applications requiring predictable performance and high space efficiency.
Developers should learn cuckoo hashing when building systems that demand guaranteed fast lookups, such as network routers, caching layers, or real-time databases, where worst-case performance is critical. It is also valuable in memory-constrained environments due to its high load factor tolerance, often achieving over 90% occupancy without significant performance degradation. Use cases include implementing associative arrays in high-performance computing or security applications like intrusion detection systems that require rapid key-value lookups.