What is the performance of hash tables in C++11?

What is the performance of hash tables in C++11?

In C++11, hash tables are implemented using the unordered_map and unordered_set containers. They offer average-case constant time complexity O(1) for insertions, deletions, and lookups, but can degrade to O(n) in the worst case due to collisions.

What factors affect the performance of hash tables?

Several factors can affect hash table performance, including the quality of the hash function, the load factor, and how collisions are handled. A good hash function minimizes collisions, while a lower load factor generally improves performance.

How can I improve the performance of my hash table?

To improve hash table performance, you can choose a better hash function, resize the table when the load factor exceeds a certain threshold, and use techniques like chaining or open addressing to handle collisions more effectively.

Are there any drawbacks to using hash tables?

Yes, hash tables can have drawbacks such as increased memory usage, potential performance degradation due to collisions, and the need for a good hash function. Additionally, they do not maintain order, which can be a limitation for certain applications.