C++ unordered_set Purpose Explained

In C++, unordered_set is a container for unique elements without any order. It is implemented based on hash tables, so the average time complexity for operations like searching, insertion, and deletion is constant O(1).

The primary function of an unordered_set is to store a group of unique elements and efficiently perform operations such as finding, inserting, and deleting elements. Unlike ordered sets, unordered_sets do not sort elements, making insertion and searching faster. However, unordered_sets do not support iterating through elements in a specific order.

One of the key features of the unordered_set is its ability to quickly locate the corresponding storage position based on the element’s hash value, making it suitable for efficient searches such as deduplication and checking for element existence.

It’s important to note that since unordered_set is unordered, its iterators are invalid and cannot guarantee the order of elements. If you need to iterate in the order of elements, you can use the ordered set container.