In a linked list, how do you insert an element at the beginning of the list?
a) By updating the pointer of the new node to point to the head and then updating the head to the new node
b) By traversing to the end of the list and inserting the element
c) By shifting all elements to the right and placing the new element at the start
d) By copying the elements to a new list with the inserted element
Answer:
a) By updating the pointer of the new node to point to the head and then updating the head to the new node
Explanation:
Inserting an element at the beginning of a linked list involves creating a new node, setting its pointer to the current head, and then updating the head pointer to point to the new node. This operation takes constant time O(1).
Unlike arrays, linked lists do not require shifting elements, making insertion at the beginning efficient. This characteristic makes linked lists a good choice when frequent insertions and deletions are needed at the head.
However, insertion at the end or in the middle of a singly linked list requires traversal and takes linear time O(n).
Reference:
DSA (Data Structures and Algorithms) MCQ Questions and Answers