Q4. List concatenation

#1

The concatenation of two list can performed in O(1) time. Which of the following variation of linked list can be used?

why it is circular linked list?? why not single linked list??

#2

hello @tasfikrahman007

We can easily concatenate two lists in O (1) time using singly or doubly linked list, provided that we have a pointer to the last node at least one of the lists. But in case of circular doubly linked lists, we will break the link in both the lists and hook them together. Thus circular doubly linked list concatenates two lists in O (1) time.