In some algorithms, it is necessary to perform operations on sets with various data. However, what is a set? A set is a collection of distinct objects without duplicated elements and without a particular order. Therefore, you can only get to know whether a given element is in the set or not. The sets are strictly connected with the mathematical models and operations, such as union, intersection, subtraction, and symmetric difference.

A set can store various data, such as integer or string values, as shown in the following diagram. Of course, you can also create a set with instances of a user-defined class, as well as add and remove elements from the set at any time.

Before seeing sets in action, it is a good idea to remind you of some basic operations that can be performed on two sets, named A and B. Let's start with the union and intersection, as shown in the following illustration. As you can see, the union (shown on the left as A∪B) is a set with all elements that belong to A...