ADT disjoint set

Consider a situation with a number of persons and following tasks to be performed on them.

1. Add a new friendship relation, i.e., a person x becomes friend of another person y.
2. Find whether individual x is a friend of individual y (direct or indirect friend)

Example:

We are given 10 individuals say,
a, b, c, d, e, f, g, h, i, j

Following are relationships to be added.
a <-> b  
b <-> d
c <-> f
c <-> i
j <-> e
g <-> j

And given queries like whether a is a friend of d
or not.

We basically need to create following 4 groups
and maintain a quickly accessible connection
among group items:
G1 = {a, b, d}
G2 = {c, f, i}
G3 = {e, g, j}
G4 = {h}

Problem : To find whether x and y belong to same group or not, i.e., to find if x and y are direct/indirect friends.

Solution : Partitioning the individuals into different sets according to the groups in which they fall. This method is known as disjoint set data structure which maintains collection of disjoint sets and each set is represented by its representative which is one of its members.

(sumber) https://www.geeksforgeeks.org/