Hash tables
Let’s start with the first data structure, which is a hash table, also known as a hash map. It allows you to map keys to particular values. One of the most important assumptions of the hash table is the possibility of a very fast lookup for a value based on the key, which should be the O(1) operation.
Imagine a hash table or a dictionary
If you want to better imagine a hash table or a dictionary, it would be worth thinking about a collection containing a lot of data, where it is crucial to quickly check whether the dictionary contains a specific key, as well as quickly retrieve the value assigned to a given key. So, think about a system that allows you to determine which country a specific IP address comes from. As you know, there are many possible IP addresses, and your system must quickly obtain information from which country the user’s request comes to select the default language version of the application. This is how a hash table and dictionary...
