Enqueue Using Linked List in DSA C - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does 'enqueue' mean in the context of a queue data structure?

Enqueue means adding an element to the end (rear) of the queue.

beginner

In a linked list implementation of a queue, where is the new node added during enqueue?

The new node is added at the rear (end) of the linked list.

intermediate

Why do we keep a 'rear' pointer in a linked list queue?

To quickly add new nodes at the end without traversing the whole list.

beginner

What happens if the queue is empty when we enqueue a new element using a linked list?

Both 'front' and 'rear' pointers are set to the new node because it is the only element.

beginner

Show the basic steps to enqueue an element in a linked list queue.

1. Create a new node with the data.<br>2. Set new node's next to NULL.<br>3. If queue is empty, set front and rear to new node.<br>4. Else, set rear's next to new node and update rear to new node.

What pointer do we update when we enqueue a new element in a linked list queue?

A tail's previous

B front

C head

D rear

We update the 'rear' pointer to point to the newly added node at the end.

When the queue is empty, what do we do during enqueue?

A Set front and rear to the new node

B Only update rear pointer

C Only update front pointer

D Do nothing

Both front and rear pointers must point to the new node as it is the only element.

What is the time complexity of enqueue operation in a linked list queue?

A O(n)

B O(log n)

C O(1)

D O(n^2)

Enqueue is O(1) because we add the new node directly at the rear using the rear pointer.

Which of these is NOT a step in enqueue using linked list?

A Traverse entire list to find rear

B Update rear pointer

C Update rear's next pointer

D Create new node

We do NOT traverse the list because we keep a rear pointer for direct access.

What does the 'next' pointer of the new node point to after enqueue?

A previous node

B NULL

C front node

D itself

The new node is at the end, so its next pointer is NULL.

Explain how enqueue operation works in a linked list implementation of a queue.

Think about how to add at the end efficiently.

Why is it important to maintain both front and rear pointers in a linked list queue?

Consider how operations happen at both ends.