What are the differences between a hashtable and an array?

What are the differences between a hashtable and an array?

A hashtable is a data structure that stores key-value pairs, allowing for fast data retrieval, while an array is a collection of items stored at contiguous memory locations.

Can you explain how the lookup time differs between the two?

Sure! In a hashtable, the average lookup time is O(1) due to direct indexing, whereas in an array, it is O(n) if you need to search for an item.

What are the advantages of using a hashtable over an array?

Hashtables provide faster access times for large datasets and allow for dynamic resizing, while arrays have fixed sizes and slower search times.

Are there any scenarios where an array would be better than a hashtable?

Yes, arrays are better when you need ordered data or when the size of the dataset is known and small, as they have lower memory overhead.