How do hash tables compare in performance across different scenarios?

How do hash tables compare in performance across different scenarios?

Hash tables generally offer average-case constant time complexity O(1) for lookups, insertions, and deletions. However, performance can vary based on factors like load factor, collision resolution methods, and the nature of the data.

What are the different collision resolution methods?

The main collision resolution methods include chaining, where each bucket points to a linked list of entries, and open addressing, where you find the next available slot in the array.

How does the load factor affect performance?

The load factor, defined as the number of entries divided by the number of buckets, affects performance significantly. A higher load factor can lead to more collisions, increasing the time complexity for operations.

Can you give an example of when a hash table might perform poorly?

Certainly! A hash table can perform poorly when many keys hash to the same index, leading to a long chain in chaining or increased probing in open addressing, which can degrade performance to O(n) in the worst case.