Can you explain in more detail what exactly you don't understand?
Do you understand the for-loop in line 23? Do you know what the different kinds of collections are and how they work (HashSet, ArrayList, TreeSet, LinkedList)?
Thanks for your kind consideration on the issue
Yes, i am aware the the collections and for loop specified in the program
problem statement that i am unable to understand in the program how and what exactly these statements are performaing
addRange(set1, 1);
addRange(list1, 2);
addRange(set2, 3);
addRange(list2, 5);
static void addRange(Collection<Integer> col, int step)
Those first four lines are calls to the method named addRange, where the method is called with two arguments: a collection of Integer objects and an int.